Judgment — ECLI:EU:C:2024:906
Date: 2024-10-17
Language of the case: English
Court formation: Tenth Chamber
Subject matter: Environment
Procedure: Action for failure to fulfil obligations - successful
Origin: Malta

JUDGMENT OF THE COURT (Tenth Chamber) 17 October 2024 (*) ( Failure of a Member State to fulfil obligations – Article 258 TFEU – Directive 91/271/EEC – Urban waste water treatment – Collecting systems for urban waste water in certain agglomerations – Article 4 – Secondary or equivalent treatment of urban waste water – Article 5 – Sensitive areas – More stringent treatment – Article 10 – Sufficient performance – Article 15 – Monitoring of the conformity of discharges with the requirements of Annex I.B – Control procedures laid down in Annex I.D – Maximum permitted number of samples which fail to conform ) In Case C‑304/23, ACTION for failure to fulfil obligations under Article 258 TFEU, brought on 15 May 2023, European Commission, represented by E. Sanfrutos Cano and C. Schembri, acting as Agents, applicant, v Republic of Malta, represented by A. Buhagiar, acting as Agent, and by D. Sarmiento Ramírez-Escudero, abogado, defendant, THE COURT (Tenth Chamber), composed of D. Gratsias (rapporteur), President of the Chamber, I. Jarukaitis, President of the Fourth Chamber and Z. Csehi, Judges, Advocate General: J. Kokott, 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 requests the Court to declare that: – by failing to take the measures necessary to ensure that urban waste water from the agglomerations of Malta South and Malta North entering collecting systems is, before discharge, subject to secondary treatment or an equivalent treatment, the Republic of Malta has failed to fulfil its obligations under Articles 4 and 10 of Council Directive 91/271/EEC of 21 May 1991 concerning urban waste water treatment (OJ 1991 L 135, p. 40); – by failing to take the measures necessary to ensure that urban waste water from the agglomeration of Malta North entering collecting systems is subject, before discharge into sensitive areas or their catchment areas, to more stringent treatment than that described in Article 4 of that directive, the Republic of Malta has failed to fulfil its obligations under Article 5 thereof; and – by failing to monitor discharges of urban waste water from the agglomerations of Malta South and Malta North in order to verify compliance thereof with the requirements of Annex I.B to that directive in accordance with the control procedures laid down in Annex I.D, the Republic of Malta has failed to fulfil its obligations under Article 15 of, and Annex I.B and I.D to, that directive. Legal context The 2003 Act of Accession 2 Article 24 of the Act concerning the conditions of accession of the Czech Republic, the Republic of Estonia, the Republic of Cyprus, the Republic of Latvia, the Republic of Lithuania, the Republic of Hungary, the Republic of Malta, the Republic of Poland, the Republic of Slovenia and the Slovak Republic and the adjustments to the Treaties on which the European Union is founded (OJ 2003 L 236, p. 33; ‘the 2003 Act of Accession’) provides: ‘The measures listed in Annexes V, VI, VII, VIII, IX, X, XI, XII, XIII and XIV to this Act shall apply in respect of the new Member States under the conditions laid down in those Annexes.’ 3 Annex XI to that act, entitled ‘List referred to in Article 24 of the Act of Accession: Malta’, in Chapter 10, Section C, point 3(b), provides: ‘By way of derogation from Article 4 of Directive [91/271], the requirements for treatment of urban waste water shall not fully apply in Malta until 31 March 2007 in accordance with the following intermediate targets: … – by 31 October 2006, compliance with the Directive shall be achieved for Malta North representing a further 8% of the total biodegradable load.’ Directive 91/271 4 Article 1 of Directive 91/271 states: ‘This Directive concerns the collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sectors. The objective of the Directive is to protect the environment from the adverse effects of the abovementioned waste water discharges.’ 5 Article 2 of that directive provides: ‘For the purpose of this Directive: 1. “urban waste water” means domestic waste water or the mixture of domestic waste water with industrial waste water and/or run-off rain water; … 4. “agglomeration” means an area where the population and/or economic activities are sufficiently concentrated for urban waste water to be collected and conducted to an urban waste water treatment plant or to a final discharge point; 5. “collecting system” means a system of conduits which collects and conducts urban waste water; 6. “1 p.e. (population equivalent)” means the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day; … 8. “secondary treatment” means treatment of urban waste water by a process generally involving biological treatment with a secondary settlement or other process in which the requirements established in Table 1 of Annex I are respected; 9. “appropriate treatment” means treatment of urban waste water by any process and/or disposal system which after discharge allows the receiving waters to meet the relevant quality objectives and the relevant provisions of this and other Community Directives; … 11. “eutrophication” means the enrichment of water by nutrients, especially compounds of nitrogen and/or phosphorus, causing an accelerated growth of algae and higher forms of plant life to produce an undesirable disturbance to the balance of organisms present in the water and to the quality of the water concerned; …’ 6 Article 4 of that directive provides: ‘1. Member States shall ensure that urban waste water entering collecting systems shall before discharge be subject to secondary treatment or an equivalent treatment as follows: – at the latest by 31 December 2000 for all discharges from agglomerations of more than 15 000 p.e.[;] – at the latest by 31 December 2005 for all discharges from agglomerations of between 10 000 and 15 000 p.e.[;] – at the latest by 31 December 2005 for discharges to fresh-water and estuaries from agglomerations of between 2 000 and 10 000 p.e. … 3. Discharges from urban waste water treatment plants described in paragraphs 1 and 2 shall satisfy the relevant requirements of Annex I.B. … 4. The load expressed in p.e. shall be calculated on the basis of the maximum average weekly load entering the treatment plant during the year, excluding unusual situations such as those due to heavy rain.’ 7 Article 5 of that same directive is worded as follows: ‘… 2. Member States shall ensure that urban waste water entering collecting systems shall before discharge into sensitive areas be subject to more stringent treatment than that described in Article 4, by 31 December 1998 at the latest for all discharges from agglomerations of more than 10 000 p.e. 3. Discharges from urban waste water treatment plants described in paragraph 2 shall satisfy the relevant requirements of Annex I B. … 4. Alternatively, requirements for individual plants set out in paragraphs 2 and 3 above need not apply in sensitive areas where it can be shown that the minimum percentage of reduction of the overall load entering all urban waste water treatment plants in that area is at least 75% for total phosphorus and at least 75% for total nitrogen. 5. Discharges from urban waste water treatment plants which are situated in the relevant catchment areas of sensitive areas and which contribute to the pollution of these areas shall be subject to paragraphs 2, 3 and 4. … 7. Member States shall ensure that areas identified as sensitive following review under paragraph 6 shall within seven years meet the above requirements.’ 8 Article 10 of Directive 91/271 provides: ‘Member States shall ensure that the urban waste water treatment plants built to comply with the requirements of Articles 4, 5, 6 and 7 are designed, constructed, operated and maintained to ensure sufficient performance under all normal local climatic conditions. When designing the plants, seasonal variations of the load shall be taken into account.’ 9 Article 15(1) of that directive provides: ‘Competent authorities or appropriate bodies shall monitor: – discharges from urba[n] waste water treatment plants to verify compliance with the requirements of Annex I.B in accordance with the control procedures laid down in Annex I.D, …’ 10 Annex I to that directive, entitled ‘Requirements for urban waste water’, deals, in Section B, with requirements relating to ‘discharge from urban waste water treatment plants to receiving waters’ and, in Section D, with ‘reference methods for monitoring and evaluation of results’. Pre-litigation procedure 11 On 9 September 2015, in the context of EU Pilot procedure 7907/15/ENVI, the Commission sent the Republic of Malta a request for information in which it stated that the assessment of the available data submitted by the Maltese authorities pursuant to Article 15 of Directive 91/271, in the context of the eighth reporting exercise, revealed that, as at 31 December 2012, a number of obligations laid down in Article 4 of that directive, concerning the secondary treatment of urban waste water, had not been complied with as regards the agglomerations of Malta South and Malta North. 12 In addition, in that request for information, the Commission observed that the agglomeration of Malta North also failed to comply with the requirements laid down in Article 5 of that directive, concerning more stringent treatment, given that the treatment plant concerned rejected its effluent in areas which had been identified by the Maltese authorities on 22 April 2005 as nitrogen-sensitive areas. In accordance with Article 5(7), compliance with the requirements of Article 5 had to be ensured, for that agglomeration, within seven years of the identification of sensitive areas, that is to say, by 22 April 2012 at the latest. 13 On 8 December 2016, the Commission sent a letter of formal notice to the Republic of Malta in which it concluded, on the basis of the data received in the context of EU Pilot procedure 7907/15/ENVI, that that Member State had failed to fulfil its obligations under Articles 4, 10 and 15 of, and Annex I.B and I.D to, Directive 91/271, as regards the agglomerations of Malta South and Malta North, and under Article 5 of that directive, as regards the agglomeration of Malta North. 14 By letter of 12 April 2017, the Maltese authorities replied to that letter of formal notice. In that letter, they acknowledged that the agglomerations of Malta South and Malta North still did not comply with the relevant requirements of Directive 91/271. 15 In the light of the information provided in that letter, the Commission, on 5 October 2017, sent a reasoned opinion to the Republic of Malta in which it concluded that it did not comply with its obligations under Articles 4, 10 and 15 of, and Annex I.B and I.D to, that directive, as regards the agglomeration of Malta South, and under Articles 4, 5, 10 and 15 of, and Annex I.B and I.D to, that directive, as regards the agglomeration of Malta North. 16 The Maltese Government replied to that reasoned opinion by letters of 22 December 2017, 13 July 2018 and 8 August 2019. The case was also discussed at a ‘package’ meeting with the Maltese authorities, organised by the Commission on 25 and 26 November 2019. Following a letter from the Commission dated 23 November 2020, concerning issues raised at that meeting, the Maltese authorities sent updated information by letters of 18 March 2021, 13 August 2021 and 5 August 2022. 17 As it was not satisfied with that reply, the Commission decided to institute the present action. The action Admissibility Arguments of the parties 18 The Republic of Malta submits that the present action is inadmissible on the ground that, by bringing it almost seven years after the letter of formal notice was sent, the Commission exceeded its discretion by unreasonably extending the duration of the pre-litigation procedure. 19 In that regard, first, unlike the situation in the cases giving rise to the judgments of 12 September 2000, Commission v United Kingdom (C‑359/97, EU:C:2000:426), and of 18 July 2007, Commission v Germany (C‑490/04, EU:C:2007:430), the Commission gave no reason to justify the delay in bringing the present action. 20 Secondly, the Republic of Malta submits that it is not in a position to rely on the significant improvements made since the reasoned opinion was sent, many of which would have enabled the requirements of that directive to be satisfied, since, in accordance with settled case-law, the Court is to rule only on the facts as established as at the date on which the period laid down in the reasoned opinion expired, namely 5 December 2017. In that regard, that Member State is not in a position to rely on the case-law according to which the Court may take into consideration events occurring after that date, provided that they are of the same kind as those referred to in that opinion and constitute the same conduct, since such events are such as to establish that the alleged failure to fulfil obligations persists. 21 Thirdly, according to that Member State, the Commission thus committed an abuse of procedure by altering the balance which Article 260(2) TFEU seeks to ensure between compliance with judgments of the Court of Justice and the protection of the rights of the Member States. In the event of an action for failure to fulfil obligations under that provision, the action would be based on a judgment referring to events occurring more than half a decade before, without taking account of developments which took place at a later stage. 22 The Commission contends that the action is admissible. Findings of the Court 23 It should be recalled, first, that, according to settled case-law, it is for the Commission to choose the point in time which it considers to be appropriate for bringing an action for failure to fulfil obligations. The considerations which determine that choice cannot affect the admissibility of the action. The rules laid down in Article 258 TFEU must be applied without any obligation on the Commission to act within a specific period, subject to situations in which the excessive duration of the pre-litigation procedure is liable to make it more difficult for the Member State concerned to refute the Commission’s arguments and thus to infringe the rights of the defence. It is for the Member State concerned to adduce evidence of the effect of such excessive duration (judgment of 4 May 2017, Commission v Luxembourg, C‑274/15, EU:C:2017:333, paragraph 39 and the case-law cited). 24 Consequently, the Republic of Malta’s line of argument relating to the Commission’s lack of objective justification for the alleged delay in bringing the present action cannot succeed. 25 Secondly, with regard to the Republic of Malta’s line of argument relating to the infringement of its rights of defence, it should be noted that it is based on the incorrect premiss that the period within which the Commission brought the present action prevented the Republic of Malta from relying on the significant improvements made since the reasoned opinion was sent. 26 Suffice it to note, in that regard, that, as the Republic of Malta itself acknowledges, according to the settled case-law of the Court, the question of whether a Member State has failed to fulfil its obligations must be determined by reference to the situation prevailing in the Member State at the end of the period laid down in the reasoned opinion and that the Court cannot take account of any subsequent changes (judgment of 30 November 2023, Commission v Slovenia (Urban waste water treatment), C‑328/22, EU:C:2023:939, paragraph 43 and the case-law cited). 27 As the Republic of Malta itself acknowledges, the application of that case-law cannot be called into question by the case-law according to which the subject matter of an action for 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 5 April 2017, Commission v Bulgaria, C‑488/15, EU:C:2017:267, paragraph 43 and the case-law cited). The latter case-law is relevant only in so far as the Commission’s action seeks to raise a systematic and persistent failure to fulfil obligations under EU law, so that the production, by that institution, 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 5 April 2017, Commission v Bulgaria, C‑488/15, EU:C:2017:267, paragraph 42 and the case-law cited). 28 Thirdly, as regards the alleged impact of the date on which the present action was brought on the balance which Article 260(2) TFEU seeks to ensure between compliance with the judgments of the Court and the protection of the rights of the Member States, which, according to the Republic of Malta, would result in an ‘abuse of procedure’, it should be recalled that the relevant reference date for assessing whether there has been a failure to fulfil obligations under that provision is the date of expiry of the period prescribed in the letter of formal notice issued under that provision, and not the date of expiry of the period prescribed in the reasoned opinion issued under the first paragraph of Article 258 TFEU (see, to that effect, judgment of 14 December 2023, Commission v Romania (Closure of landfill sites), C‑109/22, EU:C:2023:991, paragraph 37 and the case-law cited). 29 Furthermore, it is also apparent from the case-law that, in the context of the procedure referred to in Article 260(2) TFEU, the date on which the Commission brought a matter before the Court, on the basis of the second paragraph of Article 258 TFEU, for a declaration that a Member State has failed to fulfil its obligations is irrelevant for the purposes of fixing a lump sum or penalty payment. By contrast, the imposition of financial penalties in the context of that procedure depends, inter alia, on the conduct of the Member State concerned and, in particular, on the speed with which it takes the measures necessary to put an end to the infringement established and to ensure full compliance with the judgment which made that finding (see, to that effect, judgment of 12 November 2019, Commission v Ireland (Derrybrien Wind Farm), C‑261/18, EU:C:2019:955, paragraphs 120, 123 and 130 and the case-law cited). 30 It is apparent from the foregoing considerations that the present action is admissible. The first complaint Arguments of the parties 31 By its first complaint, the Commission complains that the Republic of Malta has failed to take the measures necessary to ensure that urban waste water from the agglomerations of Malta South and Malta North entering collecting systems is, before discharge, subject to secondary treatment or an equivalent treatment, and for having, on that ground, failed to fulfil its obligations under Articles 4 and 10 of Directive 91/271. 32 The Commission asserts that the requirements of Article 4 of that directive are not met in respect of the same agglomerations, since the capacity of their treatment plants remains insufficient to treat the reported loads. 33 Furthermore, the Commission notes that, although the Maltese authorities have been aware of it for a long time, they have not taken the measures necessary to remedy the discharge of agricultural waste into the urban waste water system, which, according to those authorities, is the cause of the failure of the agglomerations of Malta North and Malta South to comply with the requirements of that directive, despite the unlawful nature of such a practice. Those difficulties cannot therefore, in its view, justify the infringement by the Republic of Malta of its obligations under that directive, with which, under Chapter 10, Section C, point 3(b) of Annex XI to the 2003 Act of Accession, it was required to comply by not later than 31 March 2007. 34 With regard to the failure to comply with Article 10 of Directive 91/271, the Commission submits that the infringement by the Republic of Malta of Article 4 of that directive inevitably entails an infringement of Article 10, since agglomerations which cannot achieve an adequate level of treatment of urban waste water cannot, a fortiori, achieve sufficient performance in variable local climatic conditions. It refers, in that regard, to the judgment of 5 March 2020, Commission v Cyprus (Collection and treatment of urban waste water) (C‑248/19, EU:C:2020:171, paragraphs 37 and 38 and the case-law cited). 35 The Republic of Malta acknowledges, with regard to the agglomeration of Malta South, that compliance with the requirements of Article 4 of that directive will not be ensured until 2026. 36 By contrast, according to that Member State, the first ground of complaint is unfounded, in so far as that complaint alleges infringement of Article 10 of that directive with regard to that agglomeration. The Maltese authorities explained, during the pre-litigation stage, that the peak week load had been distorted by the discharge of agricultural waste and did not result from seasonal peaks, which had indeed been taken into account when designing the treatment plant of that agglomeration. 37 As regards the agglomeration of Malta North, the Republic of Malta considers that, if the Court were to accept evidence subsequent to the expiry of the period laid down in the reasoned opinion, it would have to take into consideration the significant improvements made so far. 38 Furthermore, with regard to the capacity of the urban waste water treatment plants of the agglomerations concerned to reduce the chemical oxygen demand, the Republic of Malta lists the temporary solutions used to divert agricultural waste from those treatment plants, which were the cause of the previous infringements. That being so, that Member State expects full compliance with Directive 91/271 to be achieved by the end of 2025. Findings of the Court 39 Pursuant to Article 4(1) of Directive 91/271, Member States are to ensure that urban waste water entering collecting systems shall, before discharge, be subject to secondary treatment or an equivalent treatment. 40 More specifically, Article 4(3) of Directive 91/271 provides, inter alia, that the discharges from urban waste water treatment plants described in Article 4(1) and (2) must satisfy the relevant requirements of Annex I.B to that directive. Furthermore, under Article 4(4), the load expressed in p.e. is to be calculated on the basis of the maximum average weekly load entering the treatment plant during the year, excluding unusual situations such as those due to heavy rain. 41 In accordance with Chapter 10, Section C, point 3(b) of Annex XI to the 2003 Act of Accession, by way of derogation from Article 4, the requirements laid down by that article for urban waste water treatment did not fully apply in Malta until 31 March 2007. 42 Since the agglomerations of Malta South and Malta North had a load expressed in p.e. of more than 15 000, they therefore had, since that date, to have treatment plants which would allow their urban waste water to be subjected to secondary treatment under the conditions laid down in Article 4 of Directive 91/271 and to ensure, in particular, in accordance with Article 4(3) thereof, that discharges from the treatment plants concerned satisfy the requirements of Annex I.B to that directive. To that end, those treatment plants had to have a capacity corresponding to the total load of those agglomerations expressed in p.e., calculated, in accordance with Article 4(4) of that directive, on the basis of the maximum average weekly load entering those treatment plants during the year, excluding unusual situations such as those due to heavy rainfall. 43 It is apparent from the file submitted to the Court that, in the light of the latest information that was available to the Commission when it issued the reasoned opinion, the capacity of the treatment plants associated with the Malta South agglomeration was 500 000 p.e. whereas the peak week load reported was 674 870 p.e. As for the Malta North agglomeration, it had a capacity of 60 000 p.e. and a peak week load of 120 900 p.e. 44 Thus, it was apparent from that information that some of the urban waste water discharged by those agglomerations did not receive any treatment, with the result that those discharges did not meet the requirements of Article 4(1) of Directive 91/271 nor those of Article 4(3) thereof, since those discharges were not capable, by definition, of complying with the requirements of Annex I.B to that directive, in the absence of any secondary treatment (see, to that effect, judgment of 28 March 2019, Commission v Ireland (System for collecting and treating waste water), C‑427/17, EU:C:2019:269, paragraphs 153 and 154 and the case-law cited). 45 The information from the latest available status report, relating to 2018, published by the Maltese authorities and sent to the Commission in 2020, corresponding to the period immediately after the deadline set in the reasoned opinion, shows a capacity of 620 000 p.e. for the agglomeration of Malta South and 80 000 p.e. for that of Malta North, whereas those agglomerations generated a load of 732 620 p.e. and 128 025 p.e. respectively. 46 Indeed, subsequently, in their letter of 18 March 2021, the Maltese authorities indicate ‘estimated’ urban loads of 568 000 p.e. and 91 000 p.e. respectively. However, as it transpires from that letter, those loads are only a simple estimate and do not constitute, in the same way as the loads indicated in the status report referred to in the preceding paragraph, data calculated on the basis of the maximum average weekly load, in accordance with Article 4(4) of Directive 91/271. They cannot therefore, in any event, be taken into account by the Court. 47 Consequently, it is apparent from the foregoing that, on the date of expiry of the period laid down in the reasoned opinion, the treatment plants of the agglomerations of Malta South and Malta North still did not have capacity, in accordance with that article, to ensure, inter alia, secondary treatment of all the urban waste water entering the treatment plants of those agglomerations, so that the discharges from those plants satisfy the requirements of Annex I.B to that directive. 48 Moreover, the Republic of Malta does not dispute that the capacities of those treatment plants were, at that date, insufficient, with that Member State stating that the overload of those plants is the result of the entry into those installations of agricultural waste and that their compliance with the requirements of that directive, in particular those laid down in Article 4 thereof, will not be ensured until 2026 as regards the agglomeration of Malta South, and probably not until the end of 2025 as regards the agglomeration of Malta North. 49 That finding cannot be called into question by the arguments of the Republic of Malta relating to improvements made since the expiry of the period laid down in the reasoned opinion. 50 As has been pointed out in paragraph 26 of the present judgment, the Court cannot, in accordance with settled case-law, take account of changes which have occurred after that date. 51 As regards the requirements resulting from Article 10 of Directive 91/271, it should be recalled that, in accordance with that article, Member States must ensure that urban waste water treatment plants built to comply with the requirements of Articles 4 to 7 of that directive are designed, constructed, operated and maintained to ensure sufficient performance under all normal local climatic conditions, taking into account seasonal variations of the load when designing those treatment plants. 52 Compliance with that obligation presupposes, inter alia, that the requirements laid down in Article 4 of that directive are met, with the result that it cannot be considered to be fulfilled in the agglomerations where the obligation to subject all urban waste water to secondary or equivalent treatment, as laid down in Article 4 of Directive 91/271, has not been complied with (judgment of 2 September 2021, Commission v Sweden (Waste water treatment plants), C‑22/20, EU:C:2021:669, paragraphs 61 and 62 and the case-law cited). 53 In those circumstances, having regard to the fact that, as has been found in paragraph 47 of the present judgment, on the date of expiry of the period laid down in the reasoned opinion, the treatment plants in the agglomerations of Malta South and Malta North still did not have a capacity enabling compliance with the obligations arising from Article 4 of that directive to be ensured, it must be concluded that compliance with the obligations arising from Article 10 of Directive 91/271 could not, consequently, be satisfied. 54 That finding cannot be called into question by the Republic of Malta’s argument that the Maltese authorities stated, during the pre-litigation stage, that, as regards the agglomeration of Malta South, the weekly peak load had been distorted by the discharge of agricultural waste and did not come from seasonal peaks, which had indeed been taken into account when designing the treatment plant of that agglomeration. 55 Since that treatment plant does not have the capacity to ensure treatment in accordance with the requirements of Article 4 of Directive 91/271 for all urban waste water entering that plant, it cannot be regarded as being designed, constructed, operated and maintained in such a way as to ensure sufficient performance under all normal climatic conditions of its location, irrespective of the fact that seasonal variations were taken into account when it was designed. Those considerations also apply to the treatment plant of the agglomeration of Malta North. 56 Furthermore, irrespective of the question raised by the Commission relating to conformity with EU law of the discharge of agricultural waste into collection systems intended for receiving urban waste water, it must be borne in mind that, according to settled case-law, a Member State cannot plead difficulties in its domestic legal order to justify failure to observe obligations arising under EU law, such as Directive 91/271 (judgment of 5 March 2020, Commission v Cyprus (Collection and treatment of urban waste water), C‑248/19, EU:C:2020:171, paragraph 36 and the case-law cited). 57 In the light of the foregoing, the first complaint must be upheld. The second complaint Arguments of the parties 58 By its second complaint, the Commission complains that the Republic of Malta has failed to take the measures necessary to ensure that urban waste water from the agglomeration of Malta North entering collecting systems is subject, before discharge into sensitive areas or into their catchment areas, to more stringent treatment than that described in Article 4 of Directive 91/271, and for having, on that ground, failed to fulfil its obligations under Article 5 of that directive. 59 The Republic of Malta disputes the second complaint, relying on the line of argument set out in paragraph 38 of the present judgment. Findings of the Court 60 In that regard, it is sufficient to note that, as has been pointed out in paragraphs 43 to 47 of the present judgment, on account of the insufficient capacity of the treatment plant associated with the agglomeration of Malta North, some of the urban waste water discharged by that treatment plant was still not subject to treatment, as at the date on which the period laid down in the reasoned opinion expired, with the result that it did not satisfy the requirements of Article 4 of Directive 91/271 and, in particular, failed to enable compliance with the requirements of Annex I.B to that directive, in the absence of any secondary treatment. The Commission is therefore also justified in inferring from it an infringement of Article 5 of that directive, since those discharges could not, as a result, meet the requirements of that article and, in particular, have been subject to more stringent treatment than that provided for in Article 4 of the directive (see, by analogy, judgment of 28 March 2019, Commission v Ireland (System for collecting and treating waste water), C‑427/17, EU:C:2019:269, paragraphs 182 to 184). 61 The Republic of Malta, which does not call into question the findings on which the second complaint is based, relies, however, on improvements made since the expiry of the period laid down in the reasoned opinion. 62 It has already been pointed out in paragraphs 26 and 50 of this judgment that the Court cannot take such improvements into account. In any event, the Republic of Malta acknowledges that those improvements still do not make it possible to ensure full compliance with the requirements of Directive 91/271, including those laid down in Articles 4 and 5 thereof. 63 It follows that the second complaint must be upheld. The third complaint Arguments of the parties 64 By its third complaint, the Commission complains that the Republic of Malta has failed to monitor discharges of urban waste water from the agglomerations of Malta South and Malta North in order to verify that they comply with the requirements of Annex I.B to Directive 91/271 in accordance with the control procedures laid down in Annex I.D to that directive and, consequently, that it has failed to fulfil its obligations under Article 15 of, and Annex I.B and I.D to, that directive. 65 First, the Commission asserts that the infringement by the Republic of Malta, on the one hand, of Article 4 of that directive, as regards the agglomeration of Malta South, and, on the other hand, of Articles 4 and 5 of that directive, as regards the agglomeration of Malta North, inevitably entails an infringement of Article 15 for those two agglomerations. 66 Secondly, it notes that the data sent by the Maltese authorities in their letter of 22 December 2017 revealed, for a one-year monitoring period, between June 2015 and June 2016, gaps relating to the chemical oxygen demand parameter, since the maximum number of samples which are allowed to not comply with the requirements of this parameter, expressed in concentrations and/or percentage reductions in Table 1 of Annex I.D to Directive 91/271, was exceeded during that monitoring period. 67 Thirdly, it submits that, as regards the chemical oxygen demand and the biochemical oxygen demand parameters in five days, the numerical values of the samples are not available so as to allow for a proper assessment of the analytical data. In addition, it observes that the data provided by the Maltese authorities are based on annual averages, whereas under Article 15 of that directive, read in conjunction with Annex I.D to that directive, samples must be collected every month at regular intervals during the year. That failure also constitutes an infringement of Article 15. 68 The Republic of Malta acknowledges, with regard to the Malta South agglomeration, that an infringement of Article 4 of Directive 91/271 gives rise to an infringement of Article 15 of the same directive. With regard to the Malta North agglomeration, the Republic of Malta makes no specific arguments on compliance with Article 15. Findings of the Court 69 The first indent of Article 15(1) of Directive 91/271, read in conjunction with Annex I.B and I.D thereto, imposes a continuing obligation, the purpose of which is to ensure that the discharges fulfil ‘over time’ the quality requirements which they must have satisfied since the entry into operation of the treatment plant (judgment of 5 March 2020, Commission v Cyprus (Collection and treatment of urban waste water), C‑248/19, EU:C:2020:171, paragraph 41 and the case-law cited). 70 In that regard, it is apparent from the file submitted to the Court that the data sent by the Maltese authorities in their letter of 22 December 2017, corresponding to the monitoring period between 2015 and 2016, show an insufficient number of samples complying with the parameters set out in Table 1 of Annex I to Directive 91/271, in the light of the maximum number laid down in Table 3 of that annex. 71 It must therefore be concluded that the most recent data available as at the date of expiry of the period laid down in the reasoned opinion revealed, as regards the agglomerations of Malta South and Malta North, a failure to fulfil the continuing obligation to ensure compliance with the required quality requirements, in breach of Article 15 of Directive 91/271, which, moreover, is not disputed by the Republic of Malta. 72 Accordingly, the third complaint must be upheld. 73 In the light of all of the above, it must be held that the Republic of Malta: – by failing to take the measures necessary to ensure that urban waste water from the agglomerations of Malta South and Malta North entering collecting systems is, before discharge, subject to secondary treatment or an equivalent treatment, has failed to fulfil its obligations under Articles 4 and 10 of Directive 91/271; – by failing to take the measures necessary to ensure that urban waste water from the agglomeration of Malta North entering collecting systems is, before discharge into sensitive areas or their catchment areas, subject to more stringent treatment than that described in Article 4 thereof, has failed to fulfil its obligations under Article 5 of that directive; and – by failing to monitor discharges of urban waste water from the agglomerations of Malta South and Malta North in order to verify compliance thereof with the requirements of Annex I.B to that directive in accordance with the control procedures laid down in Annex I.D to that directive, has failed to fulfil its obligations under Article 15 of, and Annex I.B and I.D to, that directive. Costs 74 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 against the Republic of Malta and the latter has been unsuccessful, it must be ordered to pay the costs. On those grounds, the Court (Tenth Chamber) hereby rules: 1. The Republic of Malta: – by failing to take the measures necessary to ensure that urban waste water from the agglomerations of Malta South and Malta North entering collecting systems is, before discharge, subject to secondary treatment or an equivalent treatment, has failed to fulfil its obligations under Articles 4 and 10 of Council Directive 91/271/EEC of 21 May 1991 concerning urban waste water treatment; – by failing to take the measures necessary to ensure that urban waste water from the agglomeration of Malta North entering collecting systems is, before discharge into sensitive areas or their catchment areas, subject to more stringent treatment than that described in Article 4 thereof, has failed to fulfil its obligations under Article 5 of that directive; and – by failing to monitor discharges of urban waste water from the agglomerations of Malta South and Malta North in order to verify compliance thereof with the requirements of Annex I.B to that directive in accordance with the control procedures laid down in Annex I.D to that directive, has failed to fulfil its obligations under Article 15 of, and Annex I.B and I.D to, that directive; 2. The Republic of Malta is ordered to pay the costs. Gratsias Jarukaitis Csehi Delivered in open court in Luxembourg on 17 October 2024. A. Calot Escobar K. Lenaerts Registrar President * Language of the case: English.