JUDGMENT OF THE COURT (Seventh Chamber)

4 March 2021 ([\*](#Footnote*))

(Failure of a Member State to fulfil obligations – Environment – Directive 2008/50/EC – Ambient air quality – Article 13(1) and Annex XI – Systematic and persistent exceedance of the limit values for nitrogen dioxide (NO2) in certain areas of the United Kingdom – Article 23(1) – Annex XV – Exceedance period to be ‘as short as possible’ – Appropriate measures)

In Case C‐664/18,

ACTION for failure to fulfil obligations under Article 258 TFEU, brought on 23 October 2018,

**European Commission,** represented initially by J. Norris and K. Petersen, and subsequently by E. Manhaeve and J. Norris, acting as Agents,

applicant,

v

**United Kingdom of Great Britain and Northern Ireland,** represented by F. Shibli, acting as Agent, assisted by J. Kerr Morrison, Barrister,

defendant,

supported by:

**Federal Republic of Germany,** represented initially by T. Henze and S. Eisenberg, and subsequently by J. Möller and S. Eisenberg, acting as Agents, assisted by U. Karpenstein, F. Fellenberg and K. Dingemann, Rechtsanwälte,

intervener,

THE COURT (Seventh Chamber),

composed of A. Kumin (Rapporteur), President of the Chamber, T. von Danwitz and P.G. Xuereb, Judges,

Advocate General: M. Szpunar,

Registrar: A. Calot Escobar,

having regard to the written procedure,

having decided, after hearing the Advocate General, to proceed to judgment without an Opinion,

gives the following

**Judgment**

1        By its application, the European Commission asks the Court to declare that

by systematically and persistently exceeding, first, the annual limit value for Nitrogen Dioxide (NO2), namely in the zones UK0001 (Greater London urban area); UK0002 (West Midlands urban area); UK0003 (Greater Manchester urban area); UK0004 (West Yorkshire urban area); UK0013 (Teesside urban area); UK0014 (The Potteries); UK0018 (Kingston upon Hull); UK0019 (Southampton urban area); UK0024 (Glasgow urban area); UK0029 (Eastern); UK0031 (South East); UK0032 (East Midlands); UK0033 (North West & Merseyside); UK0034 (Yorkshire & Humberside); UK0035 (West Midlands) and UK0036 (North East) and, second,

the hourly limit value for NO2 in the area UK0001 (Greater London urban area) since the entry into force of those limit values on 1 January 2010, the United Kingdom of Great Britain and Northern Ireland has failed to fulfil its obligations under the combined provisions of Article 13(1) and of Annex XI to Directive No 2008/50/EC of the European Parliament and of the Council of 21 May 2008, on ambient air quality and cleaner air for Europe (OJ 2008 L 152, p. 1),

and

by failing to adopt, as from 11 June 2010, appropriate measures to ensure compliance with the limit values for NO2 in all those zones, the United Kingdom of Great Britain and Northern Ireland has failed to meet its obligations under Article 23(1) of Directive 2008/50, read in combination with Annex XV to that directive and, in particular, the obligation laid down in the second subparagraph of Article 23(1) to ensure that the period of exceedance of limit values is kept as short as possible.

2        Notwithstanding the fact that the Commission’s application does not expressly request a declaration by the Court that the limit values fixed for NO2 were exceeded systematically and persistently, it is appropriate to consider its first plea from that perspective, given that it is clear, in particular from paragraph 40 of the application, that such a declaration was sought.

**Legal context**

***Directive 96/62/EC***

3        Article 8 of Council Directive 96/62/EC of 27 September 1996 on ambient air quality assessment and management (OJ 1996 L 296, p. 55), entitled ‘Measures applicable in zones where levels are higher than the limit value’, provided in paragraphs 1, 3 and 4:

‘1.      Member States shall draw up a list of zones and agglomerations in which the levels of one or more pollutants are higher than the limit value plus the margin of tolerance.

...

3.      In the zones and agglomerations referred to in paragraph 1, Member States shall take measures to ensure that a plan or programme is prepared or implemented for attaining the limit value within the specific time limit.

The said plan or programme, which must be made available to the public, shall incorporate at least the information listed in Annex IV.

4.      In the zones and agglomerations referred to in paragraph 1, where the level of more than one pollutant is higher than the limit values, Member States shall provide an integrated plan covering all the pollutants concerned.’

***Directive 1999/30/EC***

4        Council Directive 1999/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air (OJ 1999 L 163, p. 41), provided in Article 4, entitled ‘Nitrogen dioxide and oxides of nitrogen’:

‘1.      Member States shall take the measures necessary to ensure that concentrations of nitrogen dioxide and, where applicable, of oxides of nitrogen, in ambient air, as assessed in accordance with Article 7, do not exceed the limit values laid down in Section I of Annex II as from the dates specified therein.

The margins of tolerance laid down in Section I of Annex II shall apply in accordance with Article 8 of Directive 96/62/EC.

2.      The alert threshold for concentrations of nitrogen dioxide in ambient air shall be that laid down in Section II of Annex II.’

5        As regards protecting human health, Annex II to Directive 1999/30 laid down that the limit values for NO2 were to be complied with effect from January 2010.

6        Under Article 12 of that directive, the Member States were to bring into force the laws, regulations and administrative provisions necessary to comply with that directive by 19 July 2001.

 Directive 2008/50

7        Directive 2008/50, which entered into force on 11 June 2008, replaced five pre-existing legislative acts on ambient air quality assessment and management, including Directives 96/62 and 1999/30 which were repealed with effect from 11 June 2010 as is apparent from Article 31 of Directive 2008/50.

8        Recitals 17 and 18 of Directive 2008/50 state:

‘(17)      The necessary [EU] measures to reduce emissions at source, in particular measures to improve the effectiveness of [EU] legislation on industrial emissions, to limit the exhaust emissions of engines installed in heavy duty vehicles, to further reduce the Member States’ permitted national emissions of key pollutants and the emissions associated with refuelling of petrol cars at service stations, and to address the sulphur content of fuels including marine fuels should be duly examined as a priority by all institutions involved.

(18)      Air quality plans should be developed for zones and agglomerations within which concentrations of pollutants in ambient air exceed the relevant air quality target values or limit values, plus any temporary margins of tolerance, where applicable. Air pollutants are emitted from many different sources and activities. To ensure coherence between different policies, such air quality plans should where feasible be consistent, and integrated with plans and programmes prepared pursuant to Directive 2001/80/EC of the European Parliament and of the Council of 23 October 2001 on the limitation of emissions of certain pollutants into the air from large combustion plants [(OJ 2001 L 309, p. 1)], Directive 2001/81/EC [of the European Parliament and of the Council of 23 October 2001 on national emission ceilings for certain atmospheric pollutants (OJ 2001 L 309, p. 22)] and Directive 2002/49/EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment and management of environmental noise [(OJ 2002 L 189, p. 12)]. Full account will also be taken of the ambient air quality objectives provided for in this Directive, where permits are granted for industrial activities pursuant to Directive 2008/1/EC of the European Parliament and of the Council of 15 January 2008 concerning integrated pollution prevention and control [(OJ 2008 L 24, p. 8)].’

9        Article 1 of Directive 2008/50, entitled ‘Subject matter’, provides, in paragraphs 1 to 3:

‘This Directive lays down measures aimed at the following:

1.      defining and establishing objectives for ambient air quality designed to avoid, prevent or reduce harmful effects on human health and the environment as a whole;

2.      assessing the ambient air quality in Member States on the basis of common methods and criteria;

3.      obtaining information on ambient air quality in order to help combat air pollution and nuisance and to monitor long-term trends and improvements resulting from national and [EU] measures.’

10      Article 2 of that directive, entitled ‘Definitions’, provides, in paragraphs 5, 7 to 9, 16 to 18 and 24:

‘For the purpose of this Directive:

...

5.      “limit value” shall mean a level fixed on the basis of scientific knowledge, with the aim of avoiding, preventing or reducing harmful effects on human health and/or the environment as a whole, to be attained within a given period and not to be exceeded once attained;

...

7.      “margin of tolerance” shall mean the percentage of the limit value by which that value may be exceeded subject to the conditions laid down in this directive;

8.      “air quality plans” shall mean plans that set out measures in order to attain the limit values or target values;

...

16.      “zone” shall mean part of the territory of a Member State, as delimited by that Member State for the purposes of air quality assessment and management;

17.      “agglomeration” shall mean a zone that is a conurbation with a population in excess of 250 000 inhabitants or, where the population is 250 000 inhabitants or less, with a given population density per km2 to be established by the Member States;

18.      “PM10” shall mean particulate matter which passes through a size-selective inlet as defined in the reference method for the sampling and measurement of PM10, EN 12341, with a 50% efficiency cut-off at 10 μm aerodynamic diameter;

...

24.      “oxides of nitrogen” shall mean the sum of the volume mixing ratio (ppbv) of nitrogen monoxide (nitric oxide) and nitrogen dioxide expressed in units of mass concentration of nitrogen dioxide (μg/m3);

...’

11      Article 13 of Directive 2008/50, headed ‘Limit values and alert thresholds for the protection of human health’, provides in paragraph 1:

‘Member States shall ensure that, throughout their zones and agglomerations, levels of sulphur dioxide, PM10, lead, and carbon monoxide in ambient air do not exceed the limit values laid down in Annex XI.

In respect of nitrogen dioxide and benzene, the limit values specified in Annex XI may not be exceeded from the dates specified therein.

Compliance with these requirements shall be assessed in accordance with Annex III.

The margins of tolerance laid down in Annex XI shall apply in accordance with Article 22(3) and Article 23(1).’

12      Article 22 of that directive, entitled ‘Postponement of attainment deadlines and exemption from the obligation to apply certain limit values’, is worded as follows:

‘1.      Where, in a given zone or agglomeration, conformity with the limit values for nitrogen dioxide or benzene cannot be achieved by the deadlines specified in Annex XI, a Member State may postpone those deadlines by a maximum of five years for that particular zone or agglomeration, on condition that an air quality plan is established in accordance with Article 23 for the zone or agglomeration to which the postponement would apply; such air quality plan shall be supplemented by the information listed in Section B of Annex XV related to the pollutants concerned and shall demonstrate how conformity will be achieved with the limit values before the new deadline.

...

4.      Member States shall notify the Commission where, in their view, paragraphs 1 or 2 are applicable, and shall communicate the air quality plan referred to in paragraph 1 including all relevant information necessary for the Commission to assess whether or not the relevant conditions are satisfied. In its assessment, the Commission shall take into account estimated effects on ambient air quality in the Member States, at present and in the future, of measures that have been taken by the Member States as well as estimated effects on ambient air quality of current [EU] measures and planned [EU] measures to be proposed by the Commission.

Where the Commission has raised no objections within nine months of receipt of that notification, the relevant conditions for the application of paragraphs 1 or 2 shall be deemed to be satisfied.

If objections are raised, the Commission may require Member States to adjust or provide new air quality plans.’

13      Article 23 of Directive 2008/50, entitled ‘Air quality plans’, provides, in paragraph 1:

‘Where, in given zones or agglomerations, the levels of pollutants in ambient air exceed any limit value or target value, plus any relevant margin of tolerance in each case, Member States shall ensure that air quality plans are established for those zones and agglomerations in order to achieve the related limit value or target value specified in Annexes XI and XIV.

In the event of exceedances of those limit values for which the attainment deadline is already expired, the air quality plans shall set out appropriate measures, so that the exceedance period can be kept as short as possible. The air quality plans may additionally include specific measures aiming at the protection of sensitive population groups, including children.

Those air quality plans shall incorporate at least the information listed in Section A of Annex XV and may include measures pursuant to Article 24. Those plans shall be communicated to the Commission without delay, but no later than two years after the end of the year the first exceedance was observed.

Where air quality plans must be prepared or implemented in respect of several pollutants, Member States shall, where appropriate, prepare and implement integrated air quality plans covering all pollutants concerned.’

14      Article 27 of that directive, entitled ‘Transmission of information and reporting’, provides:

‘1.      Member States shall ensure that information on ambient air quality is made available to the Commission within the required timescale as determined by the implementing measures referred to in Article 28(2).

2.      In any event, for the specific purpose of assessing compliance with the limit values and critical levels and the attainment of target values, such information shall be made available to the Commission no later than nine months after the end of each year and shall include:

(a)      the changes made in that year to the list and delimitation of zones and agglomerations established under Article 4;

(b)      the list of zones and agglomerations in which the levels of one or more pollutants are higher than the limit values plus the margin of tolerance where applicable or higher than target values or critical levels; and for these zones and agglomerations:

(i)      levels assessed and, if relevant, the dates and periods when such levels were observed;

(ii)      if appropriate, an assessment on contributions from natural sources and from re-suspension of particulates following winter-sanding or -salting of roads to the levels assessed, as declared to the Commission under Articles 20 and 21.

3.      Paragraphs 1 and 2 shall apply to information collected as from the beginning of the second calendar year after the entry into force of the implementing measures referred to in Article 28(2).’

15      Annex XI to Directive 2008/50 lays down the following limit values for NO2:

| | | | |
| --- | --- | --- | --- |
| Averaging Period | Limit value | Margin of tolerance | Date by which limit value is to be met |
| One hour | 200 μg/m3, not to be exceeded more than 18 times a calendar year | ... 0% by 1 January 2010 | 1 January 2010 |
| Calendar year | 40 μg/m3 | ... 0% by 1 January 2010 | 1 January 2010 |

16      As regards the information that must be included in plans relating to ambient air quality, within the meaning of Article 23 of that directive, Section A of Annex XV to that directive states inter alia:

‘8.      Details of those measures or projects adopted with a view to reducing pollution following the entry into force of this Directive:

(a)      listing and description of all the measures set out in the project;

(b)      timetable for implementation;

(c)      estimate of the improvement of air quality planned and of the expected time required to attain these objectives.’

**Pre-litigation procedure**

17      On 22 September 2011, the United Kingdom submitted final air quality plans (‘the 2011 plans’) to the Commission relating to 40 zones and agglomerations in which one or more of the limit values laid down by that directive for NO2 had been exceeded during 2010. For 24 of those zones the United Kingdom submitted, pursuant to Article 22(1) of Directive 2008/50, applications for time extensions to the deadline laid down for compliance with NO2 limit values, and detailing how the limit values would be complied with by 1 January 2015 at the latest.

18      However, for 16 of those zones no application for an extension of time was submitted pursuant to Article 22 by the United Kingdom Government, even though the air quality plans that were submitted projected that the limit values would not be complied with until between 2015 and 2025.

19      By decision of 25 June 2012, the Commission, pursuant to Article 22(4) of that directive, raised objections in respect of 12 of the 24 applications for extensions referred to in paragraph 17 of this judgment. By contrast, it unconditionally approved 9 applications for time extensions and 3 other applications subject to certain conditions being met. The Commission did not comment on the plans covering the 16 zones for which no time extension to the deadline had been sought.

20      In 2012 the lawfulness of the 2011 plans was challenged before the United Kingdom Supreme Court by the non-governmental organisation ClientEarth. In a judgment delivered on 1 May 2013, that court declared that the United Kingdom had failed to fulfil its obligations under Article 13 of Directive 2008/50 regarding the limit values laid down for NO2. More specifically it held that, in 2010, the United Kingdom had exceeded one or more of the limit values for NO2 in 40 of the 43 zones and agglomerations of the United Kingdom and that, up until 2012, in the absence of any application for an extension to the time limit for complying with the limit values laid down in Directive 2008/50, it had remained in breach in 16 zones which were the same as those that are the subject of this application.

21      In the course of those proceedings, that court referred four questions to the Court of Justice concerning the interpretation and application of Directive 2008/50, to which the Court replied in its judgment of 19 November 2014, *ClientEarth* (C‐404/13, EU:C:2014:2382).

22      Following that judgment, the United Kingdom Supreme Court held, in April 2015, that a mandatory order must be made requiring the Secretary of State to prepare, in accordance with Article 23(1) of Directive 2008/50, new air quality plans in respect of those 16 zones, according to a defined timetable, which was to be submitted to the Commission not later than 31 December 2015.

23      In view of the fact that the limit values laid down for NO2 were persistently exceeded in a large number of zones and in parallel with the national court proceedings, the Commission, by letter of 19 June 2012, addressed questions to the United Kingdom regarding its compliance with the requirements of Directive 2008/50, in the context of a procedure under EU Pilot 3628/12/ENVI concerning, in particular, the possible breach of the limit values for NO2 and, hence, Article 13 of that directive for the zones at issue in the present case.

24      In the light of the United Kingdom’s response to those questions, on 21 February 2014 the Commission sent a letter of formal notice to that Member State, in which it considered that, as regards the year 2012, the United Kingdom complied with the annual limit value laid down for NO2 in only 5 zones or agglomerations, none of which were amongst the 16 zones covered by the present action. The Commission stated that in all of the 16 zones concerned the annual limit value of 40 μg/m3 had been exceeded since 2010 and was still being exceeded in those zones; and that in 2 of those 16 zones (UK0001 (Greater London urban zone) and UK0031 (South East)) the hourly limit value laid down for NO2 had also been exceeded in 2012.

25      The letter of formal notice stated, furthermore, that even though the United Kingdom had submitted to the Commission an application for an extension of the time limit for compliance with the limit values for NO2 in accordance with Article 22 of Directive 2008/50 for a certain number of zones, it had not done so for the 16 zones covered by the present action. Accordingly, no derogation from the obligation under Article 13 of that directive had been granted in respect of those zones.

26      As regards a breach of Article 23(1) of Directive 2008/50, the Commission stated that it had provisionally assessed the 2011 plans relating to the 16 zones in question and had concluded that the measures that they contained were insufficient to satisfy the requirements referred to in the second subparagraph of that provision.

27      In its response of 16 April 2014 to the letter of formal notice the United Kingdom stated that a revision of the measures set out in the 2011 plans was being carried out with the aim to ‘incorporate the latest projections and measures taken and identify what further measures need to be taken in order to keep the exceedance period to the shortest possible time in accordance with Article 23 of the directive’.

28      In December 2015, the United Kingdom published updated air quality plans for 38 of the 43 zones and agglomerations of its territory, including in respect of the 16 zones identified in the letter of formal notice and which are the subject of the present application. Those plans were officially communicated to the Commission on 17 December 2015 (‘the 2015 plans’). They anticipated compliance with the limit values, as regards zone UK0001 (Greater London urban area) by 2025, and as regards all of the other zones that are the subject of the present action, by 2020.

29      In 2016, ClientEarth brought a claim before the High Court of Justice (England and Wales) Queen’s Bench Division (Administrative Court), on the ground that the 2015 plans breached Article 23(1) of Directive 2008/50. That court upheld that claim in a judgment of 2 November 2016. Even though it did not formally strike down the 2015 plans, that court ordered that new plans be published by 24 April 2017 and notified to the Commission by 31 July 2017 at the latest.

30      On 15 February 2017, the Commission issued a letter of formal notice, which was notified to the United Kingdom on 16 February 2017, in which it concluded that that Member State had persistently failed to fulfil its obligations under Directive 2008/50. The deadline for compliance with the reasoned opinion was set at 16 April 2017.

31      The United Kingdom replied to that reasoned opinion by letter dated 12 April 2017.

32      On 26 July 2017, that Member State sent revised plans (‘the 2017 plans’) to the Commission which were supplemented by the detailed zonal plans submitted on 31 July 2017.

33      On 30 January 2018, the Commission organised a summit on air quality in Brussels in which nine Member States, including the United Kingdom, participating were facing infringement proceedings relating to the excessive air pollution due to PM10 or NO2, and for whom the next step in the proceedings was referral to the Court. The purpose of that summit was to invite those Member States to present additional binding commitments for timely, effective and credible measures to address the sources of the ongoing exceedances and to lead to compliance with the norms as soon as possible in all zones and agglomerations.

34      After having evaluated the additional information provided by the United Kingdom after that summit, the Commission concluded that the measures adopted or planned by the United Kingdom concerning the levels of NO2 would not ensure that the period during which limit values were exceeded would be as short as possible. Consequently, on 23 October 2018 the Commission lodged the present action for failure to fulfil obligations under Article 258 TFEU.

35      By decision of 19 February 2019, the President of the Court granted the Federal Republic of Germany leave to intervene in support of the form of order sought by the United Kingdom.

**The action**

***The first complaint, alleging systematic and persistent infringement of the provisions of** **Article 13****(1) of Directive 2008/50, in conjunction with** **Annex XI** **thereto***

*Arguments of the parties*

36      By its first complaint the Commission submits that the United Kingdom has systematically and persistently, since 1 January 2010, breached its obligation under Article 13(1) of Directive 2008/50, read in conjunction with Annex XI thereto, as the annual limit value for NO2 has been exceeded in the zones and agglomerations listed in paragraph 1 of this judgment and the hourly limit value has been exceeded in one of those zones, namely zone UK0001 (Greater London urban zone).

37      As a preliminary matter, citing the judgment of 5 April 2017, *Commission* v *Bulgaria* (C‐488/15, EU:C:2017:267), the Commission recalls that an objective finding that the limits values have been exceeded suffices for it to be established that there has been a breach of Article 13(1) of Directive 2008/50, as that provision lays down an obligation to achieve a particular result.

38      In the first place, the Commission recalls that the United Kingdom does not deny the breach and submits that, in its response to the reasoned opinion, that Member State stated that it ‘acknowledges, as it has done before, the breach of Article 13(1) of the directive’.

39      In the second place, the Commission submits that proof of that failure to fulfil obligations is contained in the judgments of the high courts of the United Kingdom on the matter, in particular the judgment of the United Kingdom Supreme Court of 1 May 2013 in which that court held that the United Kingdom was in breach of its obligations under Article 13 of Directive 2008/50.

40      In the third place, the Commission submits that, throughout the entire period covered by its application, the annual reports submitted by the United Kingdom Government, in accordance with Article 27 of Directive 2008/50, consistently showed exceedances of the annual limit value laid down for NO2 in the 16 zones that are the subject of the present action.

41      The initial data for 2017 shows, according to the Commission, that the 16 zones that are the subject of the present action remained in breach of the annual limit value for NO2 also in that year, however, that data has not yet been fully verified and validated.

42      As regards the hourly limit value, the Commission states that the reports submitted by the United Kingdom establish that the zone UK0001 (Greater London urban area) saw a breach in every reference year since 2010 and also in 2017. However, the latter result has not yet been fully verified and validated by the Commission.

43      The United Kingdom does not contest the breach in the zones covered by the present action of the limit values laid down for NO2 relating to the period from 2010 to 2016 inclusive. By contrast, it contends that the application for a declaration of breach covering the period after 2016 is ‘premature’ at this stage. However, in its defence, the United Kingdom declares that ‘for the avoidance of any doubt, however, [it] does not seek to argue that any of the 16 zones identified by the Commission achieved compliance in 2017 or is set to achieve compliance in 2018’.

44      The United Kingdom submits that it is not the only Member State that has had to declare breaches of Article 13 of Directive 2008/50, as 17 Member States in 2013 and 19 Member States in 2016 have reported exceedances of the limit values laid down for NO2. It considers that this situation is largely a result of the fact that vehicle emission standards fixed at EU level have not achieved the anticipated reductions of NO2 emissions, which was exacerbated by the ‘cheating’ scandal of a car manufacturer in Germany. In the same context, the United Kingdom emphasises that the non-compliance with limit values associated with diesel transport is a ‘European-wide’ challenge.

45      In its reply, the Commission submits additionally that the fact that other Member States have also breached Directive 2008/50 is irrelevant to the determination of whether the United Kingdom failed to fulfil its obligations under that directive. Similarly, the submissions regarding the purported principal causes of the failure by the United Kingdom to fulfil its obligations are unimportant since it is the existence and persistence of those breaches that must be established.

46      The Commission also submits that, according to the case-law of the Court, the subject matter of an action for allegedly persistent failure to fulfil obligations may extend to events that took place after the reasoned opinion, provided that they are of the same kind as the events to which the opinion referred and constitute the same conduct.

47      The Commission now presents the verified figures for 2017 and states that they demonstrate that the United Kingdom has continued to breach the annual limit value in each of the zones covered by this action, as well as the hourly limit value in the zone UK0001 (Greater London urban area) in 2017.

*Findings of the Court*

48      As a preliminary point, it must be observed that the United Kingdom does not deny having breached its obligation under Article 13(1) of Directive 2008/50 to ensure compliance with the limit values laid down for NO2 in Annex XI to that directive in the 16 zones covered by the present action for the period from 21 January 2010 until 2016 inclusive.

49      However, the United Kingdom contends that a declaration of infringement beyond 2016 is ‘premature’.

50      In that regard, it should be noted that the Commission relies, in its reply, on the air quality data for 2017 that was submitted to it by the United Kingdom pursuant to Article 27 of Directive 2008/50. While those data thus constitute facts arising after the expiry of the deadline set out in the reasoned opinion, the fact remains that they are of the same kind as the facts to which the opinion referred and constitute the same conduct, with the result that the subject matter of the present action may extend to them (judgment of 10 November 2020, *Commission* v *Italy* (Limit values – PM10) C‐644/18, EU:C:2020:895, paragraph 66 and the case-law cited).

51      Therefore, the merits of the first plea in law of the action should be analysed in the light of that information, since it merely seeks to set out in detail a complaint which the Commission had already made more generally in the application and, thus, does not alter the subject matter of the alleged failure to fulfil obligations and has no effect on the scope of the proceedings (see, to that effect, judgment of 10 November 2020, *Commission* v *Italy* *(Limit values – PM10),* C‐644/18, EU:C:2020:895, paragraph 68 and the case-law cited).

52      Having made those preliminary observations, it should be noted that, as set out in Article 1(1) of Directive 2008/50, the directive lays down measures aimed at defining and establishing objectives for ambient air quality designed to avoid, prevent or reduce harmful effects on human health and the environment as a whole. In that context, the first subparagraph of Article 13(1) of that directive provides that Member States must ensure that throughout their zones and agglomerations levels of, inter alia, NO2 in ambient air do not exceed the limit values laid down in Annex XI to that directive.

53      It should be borne in mind that the complaint alleging infringement of the obligation set out in that Article 13 must be assessed taking into account the settled case-law according to which the procedure provided for in Article 258 TFEU is based on an objective finding that a Member State has failed to fulfil its obligations under the FEU Treaty or secondary legislation judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)*, C‐644/18, EU:C:2020:895, paragraph 70).

54      The Court has thus already stated on several occasions that the fact that the limit values for pollutants in ambient air were exceeded is sufficient in itself to make it possible to establish an infringement of the provisions of Article 13(1) of Directive 2008/50, in conjunction with those of Annex XI thereto (judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)*, C‐644/18, EU:C:2020:895, paragraph 71).

55      In the present case, the data contained in the annual air quality reports, submitted by the United Kingdom pursuant to Article 27 of Directive 2008/50 show that from 2010 to 2017 inclusive, the annual limit value for NO2 was exceeded in the 16 zones referred to in paragraph 1 of this judgment. It is also clear from that data that, throughout that period, the hourly limit value was exceeded in the zone UK0001 (Greater London urban area) more than 18 times per calendar year, which is the number of days for which exceedance is permitted under Directive 2008/50.

56      As regards, in particular, the exceedances of the annual limit value, the data show that, between the years 2010 and 2016 in all those zones, the stated values regularly exceeded between 25% and 75% of the limit value laid down by Directive 2008/50. In some years, the amount by which the value was exceeded was more than three times higher than the limit value laid down by Directive 2008/50 (see the zone UK0001 (Greater London urban area) for the years 2013 to 2015).

57      Likewise, the hourly limit value in zone UK0001 (Greater London urban area) was exceeded each year from 2010 until 2016 inclusive, by at least 300% of the value laid down by Directive 2008/50.

58      It follows that the exceedances thus established in those zones must be regarded as persistent and systematic, without the Commission’s being required to provide additional evidence in that regard (judgment of 10 November 2020, *Commission* v *Italy* *(Limit values – PM10)*, C‐644/18, EU:C:2020:895, paragraph 76).

59      As regards the argument put forward by the United Kingdom that it is not the only Member State to have had to declare breaches of Article 13 of Directive 2008/50, it suffices to state that a failure by another Member State to fulfil its obligations does not exonerate the United Kingdom for non-compliance with its obligations under the combined provisions of Article 13(1) of the directive and Annex XI thereto.

60      Finally, as regards the argument that, first, the failure to comply with those obligations is largely due to the fact that vehicle emission standards fixed at EU level have not achieved the anticipated reductions of NO2 emissions, which was exacerbated by the ‘cheating’ scandal of a car manufacturer in Germany and, second, that non-compliance as regards limit values associated with diesel transport is a ‘European-wide’ challenge, it must be observed that the Court has already held – besides the fact that motor vehicles subject to the standards laid down in Regulation (EC) No 715/2007 of the European Parliament and of the Council of 20 June 2007 on type approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6) and on access to vehicle repair and maintenance information (OJ 2007 L 171, p. 1), are not the only cause of emissions of NO2, or of PM10 particulate matter – EU rules applicable to type approval of motor vehicles cannot exempt Member States from their obligation to comply with the limit values established by Directive 2008/50 on the basis of the scientific knowledge and experience of the Member States so as to reflect the level deemed appropriate by the European Union and the Member States in order to avoid, prevent or reduce the harmful effects of air pollutants on human health and the environment as a whole (judgment of 10 November 2020, *Commission* v *Italy* *(Limit values – PM10)*, C‐644/18, EU:C:2020:895, paragraph 88 and the case-law cited).

61      It follows from the foregoing that the first complaint must be upheld.

***The second complaint, alleging infringement of** **Article 23****(1) of Directive 2008/50, read alone and in conjunction with** **Section****A of** **Annex XV** **to that directive***

*Admissibility*

–       *Arguments of the parties*

62      By its second complaint, the Commission submits that, since 11 June 2010, the United Kingdom has failed to fulfil its obligations under Article 23(1) of Directive 2008/50, read alone and in conjunction with Section A of Annex XV to that directive, in particular the obligation, laid down in the second subparagraph of Article 23(1) of that directive, to ensure that the period of exceedance of the limit values for NO2 is kept as short as possible.

63      In its defence, the United Kingdom contends that this complaint should be rejected as inadmissible to the extent that it relates to the period from 16 April 2017 onwards, the deadline for compliance with the Commission’s reasoned opinion in the present case.

64      In that regard, the United Kingdom submits in particular that, first, the Commission did not set out its concerns in a new reasoned opinion as regards its plans, which were drafted and published in July 2017 and completed in October 2018, nor has it engaged any form of pre-litigation procedure or any case-by-case criticism

65      In that context, the United Kingdom submits that the Court’s findings in its judgment of 5 April 2017, *Commission* v *Bulgaria*, (C‐488/15, EU:C:2017:267), regarding a continuing breach of Article 13 of Directive 2008/50 cannot be applied to breaches of Article 23(1) of that directive. The United Kingdom concludes from that judgment that a Member State must have the opportunity of responding to criticisms about specific plans in a pre-litigation procedure before the Commission seeks a declaration of a breach of Article 23(1) of Directive 2008/50 by way of proceedings under Article 258 TFEU.

66      The United Kingdom submits, furthermore, that at every stage it prepared revised air quality plans, designed to ensure that the period of exceedance was kept as short as possible. The contents of those air quality plans have developed and changed significantly over time in response to an ever-changing evidence base, as well as the particular prevailing circumstances in the areas covered by those plans. Thus the Commission could not merely point to the continuing nature of the breach of Article 13 of Directive 2008/50 to support the claim that the separate obligation under Article 23(1) of Directive 2008/50 had been, and continued to be, breached.

67      Finally, the United Kingdom invokes the principle of fairness which requires that all developments since the issuing of each set of air quality plans must be properly taken into account. According to the United Kingdom, the Commission, however, only briefly addressed the 2017 plans and failed to include them as an annex to the application. In addition, the Commission did not take into account the developments that occurred since the issuing of those plans.

68      In its reply, the Commission submits that the findings of the Court in its judgment of 5 April 2017, *Commission* v *Bulgaria* (C‐488/15, EU:C:2017:267) regarding a continuing breach of EU law are fully applicable to the present case. The central criterion for determining whether the additional evidence may be relied on after the reasoned opinion was issued was whether the matters complained of ‘were of the same kind as the events to which the opinion referred and constitute the same conduct’. That general principle is not therefore restricted only to cases that involve a breach of Article 13 of Directive 2008/50.

69      In the present case, the arguments in respect of the 2017 plans are the same or of a sufficiently similar nature as those set out in the reasoned opinion in respect of the 2015 plans, such that those plans are admissible evidence in the present proceedings.

70      The overall infringement invoked by the Commission lies in the failure of the United Kingdom Government to take the necessary measures in order to reduce as far as possible the period of non-compliance, as required by Article 23(1) of Directive 2008/50.

71      The Commission emphasises, furthermore, that it has never alleged that the mere finding of a breach of Article 13 of Directive 2008/50 was in itself sufficient for a breach of Article 23 of that directive to be established. However, it highlights that the latter provision establishes a direct link between, on the one hand, exceedance of the limit values as laid down in Article 13(1), read in conjunction with Annex XI to that directive and, on the other hand, the preparation of air quality plans. Consequently, where there is a persistent and continuing breach of Article 13, that in itself constitutes an indicator of a persistent breach of Article 23(1) of Directive 2008/50.

72      The Commission also submits that it criticised the level of detail provided for the Clean Air Zones (‘CAZ’), the introduction of which in five British towns was provided for in the 2015 plans, and the fact the local characteristics of each of those zones had not yet been determined. Given that the United Kingdom acknowledged, in its defence, that in accordance with the 2017 plans, local authorities are required to develop local plans and that the five towns concerned work according to the same timetable as that set out in the 2015 plans, the argument in respect of the CAZ remains the same and the 2017 plans constitute additional admissible evidence of that shortcoming.

73      The Commission stresses, in that context, that it criticised the measures listed for each zone to the extent that, in numerous cases, the 2017 plans merely repeated the measures foreseen in the 2015 plans. In addition, the United Kingdom does not contest the fact that it continued to the notify exceedances of the limit values for NO2 in all the zones concerned.

74      The Commission also refutes the United Kingdom’s argument alleging a breach of the principle of fairness. By asserting, first, that there is a continuing breach of Article 23(1) of Directive 2008/50, it did not fail to meet its obligation to carry out a case-by-case analysis of air quality plans to determine whether they satisfy the requirements of that directive. The 2017 plans were the subject of such an analysis and were referred to in the application, which contained a link to those plans. Second, given that, in its defence, the United Kingdom sets out detailed additional explanations concerning those plans, it is clear that that Member State has the opportunity to advance its arguments before the Court, even if the revised plans have not been the subject of a pre-litigation procedure. Moreover, the United Kingdom has not explained what arguments it would have advanced if another reasoned opinion had been issued.

75      In its rejoinder the United Kingdom states that the 2017 plans cannot be classified as the ‘same conduct’ as the 2015 plans, since the former are new plans which call for a fresh examination by the Commission in the context of a pre-litigation procedure.

76      In addition, the United Kingdom claims it suffered prejudice, due to the approach taken by the Commission, to the extent that it could not advance its arguments in support of its defence or remedy the breach alleged prior any to legal proceedings being brought. The Court’s written procedure cannot, it submits, provide a substitute for compliance with the necessary pre-litigation process.

–       *Findings of the Court*

77      It is appropriate to recall, as a preliminary observation, that, according to the settled case-law of the Court, the question whether a Member State has failed to fulfil its obligations must be determined by reference to the situation prevailing in that Member State at the end of the period laid down by the reasoned opinion and that the Court cannot take account of any subsequent changes (see, inter alia, judgment of 16 July 2020, *Commission* v *Romania (Anti-money laundering)*, C‐549/18, EU:C:2020:563, paragraph 19 and the case-law cited).

78      However, if, as is the case here, an action brought under Article 258 TFEU seeks a declaration of a systematic and persistent failure to comply with the provisions referred to, the Court allows the production of additional evidence intended, at the stage of proceedings before it, to support the proposition that the failure thus alleged is general and consistent. In such circumstances, the subject matter of an action for allegedly persistent failure to fulfil obligations may extend to events which took place after the reasoned opinion, provided that they are of the same kind as the events to which the opinion referred and constitute the same conduct (judgment of 30 April 2020, *Commission* v *Romania (Exceedance of the limit values for PM10)*, C‐638/18, not published, EU:C:2020:334, paragraphs 54 and 55 and the case-law cited).

79      That possibility is not however, contrary to the United Kingdom’s submissions, restricted to circumstances in which the breach concerned only Article 13 of Directive 2008/50.

80      Such a possibility, which reflects the established case-law of the Court, flows from the principle that, in so far as the action seeks to raise a failure of a general nature to comply with the provisions of EU law concerned, alleging in particular a systemic and consistent tolerance of situations not in accordance with those provisions, the production by the Commission of additional evidence intended, at the stage of proceedings before the Court, to support the proposition that the failure thus alleged is general and consistent cannot be ruled out in principle (see, to that effect, judgment of 26 April 2005, *Commission* v *Ireland*, C‐494/01, EU:C:2005:250, paragraph 37).

81      In that context, it should also be noted that, the Commission may clarify its initial grounds of complaint in its application provided, however, that it does not alter the subject matter of the dispute. In producing fresh evidence intended to illustrate the grounds of complaint set out in its reasoned opinion, which allege a failure of a general nature to comply with the provisions of a directive, the Commission does not alter the subject matter of the dispute (see, to that effect, judgment of 26 April 2005, *Commission* v *Ireland*, C‐494/01, EU:C:2005:250, paragraph 38).

82      In the present case, it must be observed that the failure of a general nature invoked by the Commission lies in the fact that the United Kingdom has not taken, in the air quality plans in respect of the zones covered by the present action, in view of the exceedance of the limit values for NO2 since 11 June 2010, the appropriate measures to ensure that the period of exceedance is as short as possible, as required by Article 23(1) of Directive 2008/50.

83      It follows that, in the present case, even though the 2017 plans were not referred to in the pre-litigation procedure, since those plans concern events that are of the same kind as the events to which the reasoned opinion referred and constitute the same conduct, they could therefore properly be mentioned by the Commission in support of its application for the purpose of illustrating the failures of a general nature to fulfil obligations raised by it.

84      Consequently, those plans, which the Commission did not have knowledge of until after the reasoned opinion was notified, could properly be relied on by that institution, in the context of its second plea, for the purpose of the United Kingdom being held to have failed to fulfil its obligations under the combined provisions of Article 23(1) of Directive 2008/50 and Annex XV thereto, since 11 June 2010.

85      In addition, in those circumstances, the mere fact that the Commission does not refer to a specific date to indicate the date up until which the United Kingdom failed to fulfil its obligations under those combined provisions does not suffice to result in the inadmissibility of that plea (see, to that effect, judgment of 30 April 2020, *Commission* v *Romania (Exceedance of the limit values for PM10)*, C‐638/18, not published, EU:C:2020:334, paragraph 59).

86      It follows from the foregoing that the line of argument advanced by the United Kingdom does not affect the admissibility of the second complaint raised by the Commission.

*Substance*

–       *Arguments of the parties*

87      By its second complaint, the Commission submits in essence that, since 11 June 2010, the United Kingdom has failed to fulfil its obligations under Article 23(1) of Directive 2008/50, read alone and in conjunction with Section A of Annex XV to that directive, in particular the obligation, laid down in the second subparagraph of Article 23(1) of that directive, to ensure that the period of exceedance of the limit values for NO2 can be kept as short as possible.

88      The Commission recalls, in that regard, that the second subparagraph of Article 23(1) of Directive 2008/50 establishes a direct link between, on the one hand, exceedance of the limit values for NO2, as laid down in the combined provisions of Article 13(1) of that directive and Annex XI thereto, and, on the other hand, the establishment of those plans.

89      Furthermore, according to the Commission, the Court has held the air quality plans may be adopted only on the basis of a balance between the aim of minimising the risk of pollution and the various opposing public and private interests. Therefore, it follows from the second subparagraph of Article 23(1) of Directive 2008/50 that, while Member States have a degree of discretion in deciding which measures to adopt, those measures must, in any event, ensure that the period during which the limit values are exceeded is as short as possible.

90      In order to determine whether an air quality plan provides for appropriate measures so that the period of exceedance is as short as possible, which requires a case-by-case analysis, the Commission relies on several factors derived, in particular, from the relevant case-law.

91      First, the Commission submits that the longer the period of exceedance of the limit values in a specific zone, the more that shows that the measures proposed in the air quality plan are not sufficient or appropriate to combat the source of the emissions. In its judgment of 5 April 2017, *Commission* v *Bulgaria* (C‐488/15, EU:C:2017:267, paragraphs 115 to 117), the Court of Justice classified the persistent failure of a Member State to comply with the limit values for PM10, found more than three years after expiry of the deadline for implementation of the directive, to be ‘systematic and continuous’. It is also clear from that judgment that the classification by the Court of the exceedance of limit values over several years as ‘systematic and continuous’ proves of itself, without the need to examine in detail the content of the plans drawn up by the Member State concerned, that that Member State has not implemented appropriate and effective measures to keep the period of exceedance of the limit values for a pollutant ‘as short as possible’.

92      Secondly, the Commission submits that the Court has held that lengthy time periods for compliance with limit values, which would allow the Member State concerned to put an end to exceedances only 10, or even 14 years, after the date on which those exceedances were found, was not justified by exceptional difficulties. Consequently, plans that contemplate compliance with limit values only in the long term do not appear to be compatible with the obligation to ensure that the period of exceedance is as short as possible.

93      Thirdly, according to the Commission, another indicator of the insufficiency of the measures provided for in an air quality plan is where the trend shows an increasing or stagnant compliance gap between the limit values and the reported levels. Even if the trend is a decreasing compliance gap, where the degree to which the decrease in levels is limited compared to the size of the compliance gap as a whole, that is also an indicator that additional, more ambitious measures are necessary to ensure compliance.

94      Fourthly, the Commission submits that the size of the compliance gap, namely the difference between the limit values for NO2 and the levels measured in the ambient air, are also an indicator showing whether the measures are sufficiently ambitious. Severe and prolonged exceedances can have a particularly serious impact on the health of a population and in themselves constitute an important indication of a breach of the second subparagraph of Article 23(1) of Directive 2008/59. Similarly, the fact that not only the annual limit value but also the hourly limit value has been exceeded in a given zone is an indication of the severity of the compliance gap.

95      Fifthly, the formal content of the air quality plans should be taken into account, in particular whether they contain all the information required in Section A of Annex XV to Directive 2008/50.

96      Sixthly, as regards the material content of the air quality plans, the Commission submits that the measures provided for therein should enable the main causes of exceedance situations to be addressed. It is necessary, inter alia, to determine whether the measures taken are legally binding, sufficient and adequately resourced to enable their practical and timely implementation.

97      The Commission acknowledges that each of the 16 zones covered by the present action was formally the subject of an air quality plan at the date of expiry of the deadline set in the reasoned opinion, namely 16 April 2017. However, the Commission is of the opinion that those plans are ineffective since they have not brought to an end the exceedance situations persistently present in the United Kingdom since 2010. Such a situation should be regarded as proving of itself, without the need to examine in detail the content of the plans, that, in the present case, the United Kingdom has not implemented appropriate and effective measures to keep the exceedance period for limit values for NO2 concentrations as ‘short as possible’, within the meaning of the second subparagraph of Article 23(1) of Directive 2008/50.

98      Furthermore, and in any event, the Commission submits that a case-by-case analysis of each of the plans for the quality of the air in question, as well as the additional information provided by the United Kingdom during the pre-litigation procedure, shows that none of those plans contain measures that are appropriate for reducing as far as possible the period during which the limit values are exceeded.

99      According to the Commission, each of the 2015 plans include an overview document (‘the overview document’) and a list of measures at the level of the United Kingdom and its constituent nations, a technical report (‘the technical report’) and an individual plan for the zone concerned, together with a list of measures. That institution submits that it evaluated the sufficiency of the various measures listed for each zone, in conjunction with the matters set out in the overview document and the technical report.

100    Noting that the individual plans presented by the United Kingdom in respect of the 16 zones concerned follow a similar format, the Commission submits, first, that those plans do not meet the requirements set out in paragraph 8(c) of Annex XV to Directive 2008/50, as they do not provide an estimate of the improvement of air quality planned and of the expected time required to attain those objectives. In particular, there is no assessment of the total effects of all the planned measures in all the zones. The only measures that have been assessed and modelled are the CAZ proposed in London, Birmingham, Leeds, Southampton and Derby.

101    Secondly, according to the Commission, the projections relied on to calculate the timetables for compliance with Directive 2008/50 are ‘unrealistically optimistic’. It is clear from the domestic legal proceedings that the United Kingdom Government had been aware of that.

102    Thirdly, the Commission first of all criticises the 2015 plans for lacking the necessary ambition and urgency to address the main sources of NO2 emissions, in particular emissions from the transport sector, whose contribution to NO2 in ambient air, especially in urban areas, is particularly high. Consequently, measures to tackle NO2 pollution should address traffic volumes, the fuels used and driving behaviour. They could include systems of restriction of access applicable to high polluting vehicles, or access restrictions imposed on the most polluting vehicles in certain urban areas. The promotion of hybrid or electric or other ‘zero emission’ vehicles would also have a positive effect.

103    Despite this, only 5 of the 16 zones concerned included plans to introduce a CAZ. That ‘lack of ambition’ is, according to the Commission, supported by the findings of the High Court of Justice (England and Wales) Queen’s Bench Division (Administrative Court) in its judgment of November 2016, in which it was concluded that the time limits for compliance chosen were not compatible with the need to ensure compliance with the requirements of Directive 2008/50 within the shortest time possible, and that the periods chosen appeared moreover to be focused on maintaining the pre-existing five year cycles for monitoring and preserving administrative convenience.

104    Furthermore, the Commission submits that the five CAZ proposed, referred to in paragraph 100 of this judgment, display a number of weaknesses, despite being the only measures that have been modelled by the United Kingdom Government. In particular, their year of implementation, namely 2020 (2025 for London), appears to have been selected at random. Moreover, the Commission criticises the lack of a legal framework to enable local authorities to implement and enforce CAZ. Finally, only the CAZ in London proposed to cover all vehicles, including cars.

105    Next, the Commission sets out an analysis of the individual plans for each zone concerned in which it indicates a number of deficiencies in the implementation of those plans.

106    Finally, the Commission observes that, on 26 July 2017, the United Kingdom submitted the 2017 plans which followed a similar format to the 2015 plans and were comprised of four documents, namely an overview of the plan for tackling roadside NO2 concentrations, a details plan for tackling roadside NO2 concentrations (‘the details plan 2017’), and a technical report concerning the latter plan and the document ‘Environment Act 1995 (Feasibility Study for Nitrogen Dioxide Compliance) Air Quality Direction 2017’. On 31 July 2017, the United Kingdom communicated a link to the local plans covering, amongst others, the 16 zones that are the subject of this action.

107    The Commission submits that, despite the 2017 plans being submitted after the deadline fixed in the reasoned opinion had expired, in any event those new plans were also deficient and do not therefore remedy the breach of Article 23 of Directive 2008/50.

108    In that regard, the Commission submits that the 2017 plans not only fail to anticipate any reduction in the projected time period for compliance with Directive 2008/50, but, in most cases, predict an even longer period until such compliance is achieved. Given that the projected period of non-compliance is relevant for the assessment of the legality of the measures proposed, the Commission submits that it is a clear indicator of the fact that the 2015 plans were unduly optimistic and that the measures contained therein were inadequate. It was also an indicator that the 2017 plans were inadequate. In any event, those plans should have been more ambitious than the 2015 plans.

109    In addition, the Commission submits that the 2017 plans indicate that the setting up of a CAZ is the most effective way of ensuring compliance with Directive 2008/50 for the majority of exceedances. However, the Details Plan 2017 advises local authorities to consider setting up a CAZ only as a last resort.

110    Similarly, while Annex K of the details plan 2017 identifies 45 local authorities located in zones where limit values are exceeded, that plan concludes that those local authorities are not required to carry out feasibility studies. Given that 41 of those 45 zones are in the zones covered by the present proceedings and that the High Court of Justice (England and Wales) Queen’s Bench Division (Administrative Court) found, on 21 February 2018, that that omission was a breach of the requirements of Annex XV to Directive 2008/50, the Commission submits that this should be seen as another indication that the 2017 plans do not contain sufficiently ambitious measures.

111    Finally, the Commission submits that, while the 2015 plans foresaw the necessity for the central authorities of the United Kingdom to require local authorities to set up CAZ in six key towns, the 2017 plans no longer provide for that requirement, such an obligation having been transferred to local level. As that measure is likely to further delay the process of prospective compliance, it should be regarded as an indication that the 2017 plans are less ambitious than those of 2015.

112    While the United Kingdom accepts that for the reasons found in the national court proceedings, the 2015 plans were inadequate, it contends, however, that the action should be dismissed to the extent that the Commission seeks a declaration that those plans were illegal for reasons other than those given in the domestic proceedings. That Member State submits furthermore that, while it acknowledges having breached Article 13 of Directive 2008/50, that is not sufficient to establish that there was a breach of Article 23(1) of that directive. In any event, the United Kingdom contends that the second complaint invoked by the Commission alleging a breach of Article 23(1) should be rejected as unfounded in so far as it relates to the alleged inadequacy of the 2017 plans, including as supplemented.

113    In support of those contentions, the United Kingdom advances, in essence, three arguments. In the first place, it submits that the Commission applies an impermissible presumption in that it bases its case that a breach of Article 23(1) of Directive 2008/50 follows from the mere fact that, in the 16 zones concerned, exceedances of limit levels are continuing.

114    According to the United Kingdom, such a presumptive approach was rejected by the Court in its judgment of 5 April 2017, *Commission* v *Bulgaria* (C‐488/15, EU:C:2017:267). The Commission should therefore assess the contents of the 2015 plans in detail.

115    In that context, the United Kingdom submits that the Commission relies on the judgment of 22 February 2018, *Commission* v *Poland* (C‐336/16, EU:C:2018:94), to support the broad proposition that, if they set long-term deadlines for compliance with Directive 2008/50, air quality plans ‘appear’ to be incompatible with Article 23(1) of that directive. However, that approach is based on a misreading of that judgment, from which, in reality, it does not follow that a long-term deadline for compliance in a given zone shows that the air quality plan at issue is incompatible with Article 23 of that directive. It is necessary to determine, on a case-by-case basis whether there are other measures that could more rapidly achieve compliance with that directive’s requirements, while also taking into account the need to balance other public and private interests.

116    In the second place, the United Kingdom submits, in essence, that to the extent that the Commission criticises the 2015 plans for reasons different from those relied on by the High Court of Justice (England and Wales) Queen’s Bench Division (Administrative Court) in the national court proceedings, those criticisms must be rejected.

117    In that regard, the United Kingdom submits, first, that the Commission focuses on the information provided in individual plans rather than the entirety of the documents making up the air quality plans. The overview document and the technical report provided indications as to the time when compliance with Directive 2008/50 was expected for each of the zones concerned. The United Kingdom adopted a systematically conservative approach and did not seek to model or predict compliance for a range of measures, which was accepted in the national proceedings. Many of the measures that were part of the 2015 plans were part of the 2017 plans but, due to that conservative approach, the United Kingdom did not rely on them when assessing when compliance could be achieved.

118    Secondly, the United Kingdom contests the argument advanced by the Commission that it knew ‘at all material times’ that the projections used in the 2015 plans were too optimistic such as to render them unlawful.

119    Thirdly, the United Kingdom submits that the introduction of CAZ was not the subject of any challenge in the decisions delivered in the domestic proceedings.

120    Fourthly, the United Kingdom contends that the Commission is wrong to submit that the 2015 plans are inadequate on the ground, in particular, that the plans for individual zones include references to earlier measures or to measures already introduced in zones where exceedances continued.

121    Fifthly, the United Kingdom disputes the Commission’s argument that, as regards the zone UK0019 (Southampton urban area), the 2015 plans in part do not comply with Directive 2008/50 because the local plans indicate that there are local developments or projects that could exacerbate emissions which will require mitigation measures. As the Commission acknowledged, the authority in question stated not only that the development concerned could have a negative impact on compliance, but also that it already proposed to introduce mitigation measures.

122    Sixthly, the concerns expressed by the Commission regarding the number of CAZ proposed in 2015 were all addressed in subsequent plans introduced since 2017, which were based on new evidence concerning road vehicle emissions.

123    In the third place, the United Kingdom submits that the 2017 plans do not provide evidence of a persistent breach of Article 23(1) of Directive 2008/50. According to the United Kingdom, the Commission has not attempted to conduct, as required, a case-by-case analysis of the plans taking into account all of the material put forward as part of the overall plan for the United Kingdom.

124    In any event, each of the indicators relied on by the Commission must be rejected. First, the Commission ignores the fact that the prediction that compliance with Directive 2008/50 would take more time was the result of changes in the available evidence. Secondly, the Commission misunderstood the approach to CAZ in the 2017 plans, a criticism regarding that approach having been rejected in the domestic legal proceedings. Thirdly, the criticism concerning the change to the United Kingdom’s approach to the mandatory introduction of CAZ for five towns was also rejected by a national court. Fourthly, in seeking to impugn the 2017 plans, the Commission relies on a partial history and ignores that substantial elements of those plans were not criticised in a national court judgment.

125    In its reply, the Commission rejects the United Kingdom’s argument that it applied an ‘impermissible presumption’, submitting that both the 2015 plans and the 2017 plans were the subject of a detailed analysis. In that context, it once again states that the level and duration of exceedances are themselves indicators of the adequacy of the measures set out in the air quality plans. In any event, the United Kingdom’s argument that the Commission relied exclusively on the exceedances of the limit values to support its conclusion that there was a breach of Article 23(1) of Directive 2008/50 should be rejected precisely because the 2015 plans and 2017 plans were the subject of a detailed analysis.

126    The Commission also submits that the fact that the national courts found the air quality plans communicated by the United Kingdom to be deficient clearly indicates that the Commission’s allegation of a breach of Article 23(1) of Directive 2008/50 is well founded. However, the Commission emphasises that it is not obliged to restrict itself to the criticisms of the air quality plans found by a court in national proceedings.

127    The United Kingdom, in its rejoinder, contends that the Commission has raised allegations that are vague, unparticularised and insufficiently reasoned to support its claim that the 2017 plans lacked ambition.

128    In addition, the United Kingdom disputes having made ‘concessions’ in its defence in respect of some complaints, beyond the finding of a breach of Article 13 of Directive 2008/50 and the legal failures in the 2015 plans and the 2017 plans identified by domestic courts.

129    The United Kingdom invites the Court properly to have regard to the fact that the 2015 plans and 2017 plans had been the subject of detailed consideration by the national courts following which the plans at issue were the subject of significant changes under strict, expedited timetables imposed by those courts.

130    The United Kingdom also submits that the Commission does not recognise that there are different solutions to exceedances in different areas, and that there is no one-size fits all solution that may be imposed by the United Kingdom Government on all local authorities in order to comply with the obligations under Article 23 of Directive 2008/50.

–       *Findings of the Court*

131    It follows from the second subparagraph of Article 23(1) of Directive 2008/50 that in the event of exceedances of the limit values for NO2 for which the attainment deadline has already expired, the Member State concerned is required to draw up an air quality plan meeting certain requirements.

132    Accordingly, that plan must set out appropriate measures, so that the exceedance period can be kept as short as possible, and may additionally include specific measures designed to protect sensitive population groups, including children. Furthermore, according to the third subparagraph of Article 23(1) of Directive 2008/50, that plan must incorporate at least the information listed in Section A of Annex XV to that directive and may include measures pursuant to Article 24 thereof. The plan is to be communicated to the Commission without delay, but no later than two years after the end of the year the first exceedance was observed.

133    As is clear from the Court’s case-law, Article 23(1) of Directive 2008/50 is of general application given that it applies, without being limited in time, to exceedances of any pollutant limit value established by that directive, after the deadline fixed for its application, whether that deadline is fixed by that directive or by the Commission under Article 22 thereof (see, to that effect, judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)*, C‐644/18, EU:C:2020:895, paragraph 132 and the case-law cited).

134    It should also be observed that Article 23 of Directive 2008/50 establishes a clear link between, on the one hand, exceedance of the limit values for NO2, as laid down in the combined provisions of Article 13(1) of that directive and Annex XI thereto, and, on the other hand, the establishment of air quality plans (judgment of 30 April 2020, *Commission* v *Romania (Exceedance of the limit values for PM10)*, C‐638/18, not published, EU:C:2020:334, paragraph 115 and the case-law cited).

135    Therefore, the United Kingdom’s argument that, through its ‘presumptive approach’, the Commission relies on exceedances in breach of Article 13 of that directive to support its allegation that Article 23(1) of Directive 2008/50 has been infringed cannot succeed. That direct link, which differs from a mere ‘presumption’, permits a finding that, where those exceedances are of a certain magnitude and duration, they are evidence that the United Kingdom has not taken the measures it is required to take.

136    Air quality plans may be adopted only on the basis of the balance between the aim of minimising the risk of pollution and the various opposing public and private interests (judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)* C‐644/18, EU:C:2020:895, paragraph 134 and the case-law cited).

137    Therefore, the fact that a Member State has exceeded the limit values for NO2 is not in itself sufficient to find that that Member State has failed to fulfil its obligations under the second subparagraph of Article 23(1) of Directive 2008/50 (judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)* C‐644/18, EU:C:2020:895, paragraph 135 and the case-law cited).

138    However, it follows from the second subparagraph of Article 23(1) of Directive 2008/50 that while Member States have a degree of discretion in deciding which measures to adopt, those measures must, in any event, ensure that the period during which the limit values are exceeded is as short as possible (judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)* C‐644/18, EU:C:2020:895, paragraph 136 and the case-law cited)

139    In those circumstances, it is necessary to ascertain on the basis of a case-by-case analysis whether the plans drawn up by the Member State concerned comply with the second subparagraph of Article 23(1) of Directive 2008/50 (judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)* C‐644/18, EU:C:2020:895, paragraph 137 and the case-law cited)

140    It should recalled, at the outset, that the United Kingdom has admitted, in its written observations, that there were deficiencies in the 2015 plans for the reasons found in the national court proceedings. However, that Member State submits that the action should be dismissed to the extent that the Commission seeks a declaration that those plans were unlawful for reasons other than those found in the national court proceedings.

141    In that regard, it suffices to observe that the Commission’s discretion as to the question whether an air quality plan fails to comply with Article 23 of Directive 2008/50 cannot be restricted to substantive questions raised or complaints upheld by a court in national proceedings and that that institution is not bound by the findings of such a court in a judgment delivered in such proceedings, however those elements may constitute indications in favour of or against a finding of such an infringement of the obligations under that provision of EU law.

142    The same is true of the Court’s jurisdiction in respect of an action for infringement pursuant to Article 258 TFEU, in the context of which it is in no way bound by the findings of a national court.

143    In the present case, it must be held, as regards the limit values for NO2, the United Kingdom has systematically and persistently failed to fulfil its obligations under the provisions of Article 13(1) of Directive 2008/50 combined with Annex XI thereto in the zones concerned by the present action, between 2010 and 2017, as is apparent from the examination of the first complaint raised by the Commission. Furthermore, it must be observed, as stated in paragraph 56 and 57 of this judgment, that the magnitude by which the limit values were exceeded during that period was considerable.

144    In that context it should be recalled that the obligation, in the event of the limit values in ambient air being exceeded, to adopt air quality plans has been required of the Member State concerned since 11 June 2010. Therefore, with effect from that date, by which the United Kingdom was to have brought into force the laws, regulations and administrative provisions necessary to comply with Directive 2008/50, in accordance with Article 33(1) of that directive, that Member State was, therefore, required to adopt and implement as swiftly as possible appropriate measures pursuant to Article 23(1) of that directive.

145    In the present case, it must be held that the United Kingdom did indeed adopt, over the course of 2015, air quality plans as well as various measures intended to improve air quality in the zones in question. It is however necessary to point out that, under the third subparagraph of Article 23(1) of Directive 2008/50, those plans must incorporated at least the information listed in Section A of Annex XV of that directive.

146    It is clear from the information in the case file that the plans in question, despite providing for certain measures aimed at reducing exceedance levels, first, do not contain the required information listed in Annex XV, paragraph 8(c), to Directive 2008/50, to the extent that they do not provide an estimate of the improvement of air quality planned, even though that information is of fundamental importance. That omission is, moreover, expressly acknowledged in paragraph 52 of the Overview Document. In fact, the only measures that have been assessed and modelled are the CAZ proposed in London (UK0001 Greater London urban area), Birmingham (UK0002 West Midlands urban area), Leeds (UK0004 West Yorkshire urban area), Southampton (UK0019 Southampton urban area) and Derby (UK0032 East Midlands).

147    Second, the description of the measures set out in the 2015 plans are often insufficiently detailed, summary or vague, in particular those contained in the plans for the zones UK0001 (Greater London urban area), UK0003 (Greater Manchester urban area), UK0013 (Teesside urban area), UK0014 (The Potteries), UK0018 (Kingston upon Hull), UK0019 (Southampton area), UK0024 (Glasgow urban area), UK0032 (East Midlands), UK0033 (North West & Merseyside), UK0034 (Yorkshire & Humberside), UK0035 (West Midlands) and UK0036 (North East).

148    The 2015 plans also provide, without exception, a time period for attainment that could be of considerable duration. Thus, those plans foresee compliance with limit values for NO2 by 2020, with the exception of UK0001 (Greater London urban area) where compliance with those limit values is foreseen by 2025.

149    In addition, some of those measures are generic in that they are intended, for example, to promote certain types of transport, such as bicycles, walking or public transport, awareness campaigns and road safety in general (see zones UK0002 (West Midlands urban area), UK0003 (Greater Manchester urban area), UK0004 (West Yorkshire urban area), UK0029 (Eastern), UK0031 (South East), UK0033 (North West & Merseyside), UK0034 (Yorkshire & Humberside), UK0035 (West Midlands) and UK0036 (North East)), are not legally binding (see, for example, the plans for zones UK0004 (West Yorkshire urban area), UK0013 (Teesside urban area)) or do not directly relate to NO2 emissions, such as tree planting, the insulation of buildings and the use of solar energy (see the zones UK0001 (Greater London urban area), UK0003 (Greater Manchester urban area), UK0013 (Teesside urban area), UK0024 (Glasgow urban area), UK0029 (Eastern)).

150    Finally, in several cases, a certain number of the measures set out in the 2015 plans were in place for some time, and therefore old, or were only to be maintained for a short period, such as certain measures provided in the 2015 plans for the zones UK0001 (Greater London urban area), UK0003 (Greater Manchester urban area), UK0004 (West Yorkshire urban area), UK0029 (Eastern), UK0032 (East Midlands), UK0033 (North West & Merseyside), UK0034 (Yorkshire & Humberside) and UK0035 (West Midlands).

151    As regards the 2017 plans, it must be observed, inter alia, that they do not foresee a reduction in the time period for compliance with the obligations under Directive 2008/50 compared with what was foreseen in the 2015 plans. On the contrary, in the majority of cases the period foreseen for complying with those obligations is even longer. By way of example, the 2017 plan for the zone UK0001 (Greater London urban zone) only foresees compliance in 2026, whereas the 2015 plan foresaw compliance by 2025. As regards the zones UK0003 (Greater Manchester urban zone), UK0004 (West Yorkshire urban zone), UK0013 (Teesside urban zone), UK0014 (The Potteries), UK0029 (Eastern), UK0033 (Yorkshire & Humberside), UK0035 (West Midlands) and UK0036 (North East) the date foreseen for compliance has moved from 2020, in the 2015 plans, to 2021 in the 2017 plans. As regards the zones UK0019 (Southampton urban zone), UK0031 (South East) and UK0033 (North West & Merseyside), compliance, foreseen for 2020 in the 2015 plans, is not predicted to be achieved until 2022 in the 2017 plans. Finally, for the zone UK0024 (Glasgow urban area), the 2017 plan foresees that compliance will be achieved in 2023, whereas in the 2015 plan it was foreseen for 2020. The fact that a plan sets out a particularly long time period for achieving compliance may be taken into account for establishing that a Member State has not adopted appropriate measures in good time to ensure that the period in which the limit values for NO2 are exceeded is as short as possible in the zones concerned (see, to that effect, judgment of 10 November 2020, *Commission* v *Italy (Limit values – PM10)* C‐644/18, EU:C:2020:895, paragraphs 143 and 146).

152    The United Kingdom’s argument that its approach in the air quality plans was ‘conservative’ also cannot succeed, since it did not take into account the measures listed in the plans for individual zones in its assessment of the timetable for future compliance. As stated in paragraph 138 of this judgment, it follows from the second subparagraph of Article 23(1) of Directive 2008/50 that, while Member States have a degree of discretion in deciding which measures to adopt, those measures must, in any event, ensure that the period during which the limit values are exceeded is kept as short as possible (judgment of 30 April 2020, *Commission* v *Romania (Exceedance of limit values for PM10)*, C‐638/18, not published, EU:C:2020:334, paragraph 118 and the case-law cited).

153    Having regard to the matters set out in paragraph 143 to 152 of this judgment, it must be held that the United Kingdom has manifestly failed to adopt in good time appropriate measures to ensure that the time period during which the limit values in question are exceeded is kept as short as possible in the zones concerned. Thus, the exceedance of those limit values has remained systematic and persistent for at least seven years in those zones, despite the obligation for the Member State to take all appropriate and effective measures to comply with the requirement that the period of exceedance is kept as short as possible.

154    In the light of all the foregoing, it must be held that the arguments put forward by the United Kingdom cannot justify such long time periods for bringing to an end the proven exceedances of the limit values, having regard to the requirement to ensure that the period of exceedance is kept as short as possible.

155    It follows that the second complaint put forward by the Commission must be upheld.

156    Having regard to all the foregoing considerations, it must be held that the United Kingdom of Great Britain and Northern Ireland,

by systematically and persistently exceeding, in 16 zones of the United Kingdom, the annual limit value for NO2, namely in the zones UK0001 (Greater London urban area); UK0002 (West Midlands urban area); UK0003 (Greater Manchester urban area); UK0004 (West Yorkshire urban area); UK0013 (Teesside urban area); UK0014 (The Potteries); UK0018 (Kingston upon Hull); UK0019 (Southampton urban area); UK0024 (Glasgow urban area); UK0029 (Eastern); UK0031 (South East); UK0032 (East Midlands); UK0033 (North West & Merseyside); UK0034 (Yorkshire & Humberside); UK0035 (West Midlands) and UK0036 (North East), as well as the hourly limit value in one of those zones, namely zone UK0001 (Greater London urban area), as from 1 January 2010 until 2017 inclusive, has failed to fulfil its obligations under the combined provisions of Article 13(1) and Annex XI to Directive 2008/50,

and

by failing to adopt, as from 11 June 2010, appropriate measures to ensure compliance with the limit values for NO2 in all those zones, has failed to fulfil its obligations under the combined provisions of Article 23(1), read alone and in conjunction with Annex XV to Directive 2008/50, and in particular the obligation laid down in the second subparagraph of Article 23(1) of that directive, to ensure that the period of exceedance of limit values is kept as short as possible.

**Costs**

157    Under Article 138(1) of the Rules of Procedure of the Court of Justice, the unsuccessful party is to be ordered to pay the costs if they have been applied for in the successful party’s pleadings. Since the Commission has applied for costs and the United Kingdom has been unsuccessful, the United Kingdom must be ordered to pay the costs.

158    In accordance with Article 140(1) of the Rules of Procedure, the Federal Republic of Germany is to bear its own costs.

On those grounds, the Court (Seventh Chamber) hereby:

1.      **Declares****that the United Kingdom of Great Britain and Northern Ireland,**

**by systematically and persistently exceeding, in 16 zones of the United Kingdom, the annual limit value for Nitrogen Dioxide (NO2), namely in the areas UK0001 (Greater London urban area); UK0002 (West Midlands urban area); UK0003 (Greater Manchester urban area); UK0004 (West Yorkshire urban area); UK0013 (Teesside urban area); UK0014 (The Potteries); UK0018 (Kingston upon Hull); UK0019 (Southampton urban area); UK0024 (Glasgow urban area); UK0029 (Eastern); UK0031 (South East); UK0032 (East Midlands); UK0033 (North West & Merseyside); UK0034 (Yorkshire & Humberside); UK0035 (West Midlands) and UK0036 (North East),**

**as well as the hourly limit value for NO2 in the area UK0001 (Greater London urban area) since the entry into force of those limit values on 1 January 2010, has failed to fulfil its obligations under the combined provisions of Article 13(1) and of Annex XI to Directive No 2008/50/EC of the European Parliament and of the Council of 21 May 2008, on ambient air quality and cleaner air for Europe,**

**and**

**by failing to adopt, as from 11 June 2010, appropriate measures to ensure compliance with the limit values for NO2 in all those zones, has failed to fulfil its obligations under the combined provisions of Article 23(1), read alone and in conjunction with Annex XV to Directive 2008/50, and in particular the obligation laid down in the second subparagraph of Article 23(1) of that directive, to ensure that the period of exceedance of limit values is kept as short as possible.**

2.      **Orders the United Kingdom of Great Britain and Northern Ireland to pay, in addition to its own costs, those incurred by the European Commission.**

3.      **Orders the Federal Republic of Germany to bear its own costs.**

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| Kumin | von Danwitz | Xuereb |

Delivered in open court in Luxembourg on 4 March 2021.

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| --- | --- | --- |
| A. Calot Escobar | | A. Kumin |

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| --- | --- | --- |
| Registrar | | President of the Seventh Chamber |

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[\*](#Footref*)      Language of the case: English.