[2026] 2 S.C.R. 285 : 2026 INSC 113

The State of Tamil Nadu v.

The State of Karnataka & Anr.

(Original Suit No. 1 of 2018)

02 February 2026

[Vikram Nath* and N.V. Anjaria, JJ.]

Issue for Consideration

Matter pertains to dispute as regards the sharing of the waters of the Pennaiyar River between the State of Tamil Nadu and the State of Karnataka.

Headnotes†

Inter-State River Water Disputes Act, 1956 - ss.3, 4 - Inter- State River Pennaiyar - Dispute as regards the sharing of the waters of the Pennaiyar River and arising from the alleged construction of a check dam/diversion by the State of Karnataka-defendant-State on the said river, impeding the free flow of water, thereby depriving the State of Tamil Nadu-plaintiff-State of the benefits of the river waters flowing through the territories of Tamil Nadu and Karnataka and thereafter into Puducherry - Suit by the plaintiff-State against defendant-State and the Union of India seeking declaration that the said unilateral action of the defendant-State, illegal and violates the fundamental rights of the inhabitants of the plaintiff-State; grant permanent injunction restraining the defendant-State, from proceeding with the construction of Check Dam/diversion structure across the Pennaiyar river and its tributaries, and pumping water from them to the existing tanks in the Pennaiyar basin by the defendant-State; and other directions:

Held: Pennaiyar River water dispute has been pending consideration before this Court since the year 2018 - Multiple efforts have been undertaken by the concerned stakeholders to bring about an amicable resolution of the dispute - However, the negotiation process has not yielded any mutually acceptable outcome - In view of the inability of the parties to arrive at a common settlement,

* Author

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appropriate to call upon the Central Government to constitute a tribunal in terms of the statutory framework, so that the dispute may be adjudicated in accordance with law - In addition, the affidavit filed by the Union records that, during the ministeriallevel negotiations, the plaintiff-State unequivocally conveyed that the Pennaiyar River water dispute ought to be resolved through adjudication by a Tribunal and in view thereof, the defendant no.2 took a decision to indefinitely defer the negotiation process - Thus, issuance of direction to the Central Government to issue an appropriate notification in the Official Gazette and to constitute a Water Disputes Tribunal for the adjudication of the inter se water dispute between the parties, within the one month from the date of judgment. [Paras 7-10]

Case Law Cited

T.N. Cauvery Neerppasana Vilaiporulgal Vivasayigal Nala Urimai Padhugappa Sangam v. Union of India [1990] 3 SCR 83 : (1990) 3 SCC 440 - referred to.

List of Acts

Constitution of India; Supreme Court Rules, 2013; Inter-State River Water Disputes Act, 1956.

List of Keywords

Pennaiyar River; Inter-State River Pennaiyar dispute; Construction of check dam/diversion; Impeding free flow of water; Construction of Check Dam/ Anicut across Markandeyanadhi near Yargol village, Bangarapettai Taluk.

Case Arising From

CIVIL ORIGINAL JURISDICTION: Original Suit No. 1 of 2018

Original Suit has been instituted under Article 131 of the Constitution of India

Appearances for Parties

Advs. for the Plaintiff(s): V. Krishnamurthy AAG/Sr. Adv., P. Wilsson, N.R. Elango, G. Umapathy, Sr. Advs., Ms. Misha Rohatgi, Nakul Mohta, Amulya Upadhyay, Ayush Kashyap, Ms. Azka Sheikh Kalia, Sachin S.


Adv. for the Defendant(s): Ms. Aishwarya Bhati, A.S.G., Shashi Kiran Shetty, Advocate General, Shyam Divan, Mohan V Katarki, Sr. Advs., Ms. Chitrangda Rastravara, Pratyush Shrivastav, Sachin Sharma, Navanjay Mahapatra, Dr. N. Visakamurthy, Nishanth Patil, Mayank Jain, Ms. Addoorya Harish, Nishanth Patil.

Judgment / Order of the Supreme Court

Judgment

Vikram Nath, J.

The present suit has been instituted by the State of Tamil Nadu (hereinafter referred to as the "plaintiff-State") invoking the original jurisdiction of this Court under Article 131 of the Constitution of India, read with Part III of the Supreme Court Rules, 2013, against the State of Karnataka (hereinafter referred to as the "defendant-State") and the Union of India (hereinafter referred to as "defendant no. 2"), praying, inter alia, the grant of the following reliefs.: -

(a) Declare that the unilateral action of the defendant- State, in proceeding to construct/ having proceeded to construct new Check Dams/ Dams and diversion structures across the Pennaiyar river its tributaries, Streams etc. to divert the water by gravity or pumping, and pumping from tanks surplusing into the Pennaiyar river or its tributaries without obtaining the prior consent of the plaintiff-State is illegal and violates the fundamental rights of the inhabitants of the plaintiff-State;

(b) Grant permanent injunction restraining the defendant- State, from proceeding with the construction of Check Dam/ Anicut across Markandeyanadhi near Yargol village in Bangarapettai Taluk and construction of check dam/diversion structure across the Pennaiyar river and its tributaries, and pumping water from them to the existing tanks in the Pennaiyar basin by the defendant-State;

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(c) Direct the defendant-State to ensure the natural flows in the Pennaiyar river and its tributaries to the Plaintiff State; and

(d) Grant mandatory injunction directing the defendant- Union to take action on the plaintiff-State's letter dated 16.03.2018 with reference to construction of Dams and diversion structures and pumping schemes undertaken by the defendant-State in the Pennaiyar river; and

(e) Pass such further decree or decrees or order or orders as this Hon'ble Court may deem fit and proper in the facts and circumstances of the case.

The facts, insofar as they are relevant and material for the adjudication of the controversy at hand, are set out hereinafter:

2.1. The plaintiff-State and the defendant-State are riparian States, being two among the three basin States, along with the Union Territory of Puducherry, through which the inter-State River Pennaiyar flows. According to the plaintiff-State, the dispute centres around the sharing of the waters of the Pennaiyar River and arises from the alleged construction of a check dam/ diversion by the defendant-State on the said river, which is stated to have impeded the free flow of water, thereby depriving the plaintiff-State of the benefits of the river waters flowing through the territories of Tamil Nadu and Karnataka and thereafter into Puducherry.

2.2. In the year 1892, with a view to delineate and acknowledge the extent of the rights of the party-States in relation to the use, control and distribution of the waters of an inter-State River, an agreement came to be executed between the erstwhile States of Madras and Mysore, the predecessor States of the present plaintiff-State and defendant-State, respectively.

2.3. According to the plaintiff-State, the dispute arose upon the defendant-State taking a decision to undertake five distinct works in the Pennaiyar River Basin within its territory. It is alleged that the execution of these works would interfere with the natural flow of the river, resulting in a substantial reduction of the waters reaching the plaintiff-State and thereby adversely


impacting its water requirements. It is further asserted that the said projects have the potential to gravely affect the livelihood of lakhs of farmers in the districts of Krishnagiri, Dharmapuri, Thiruvannamalai, Villupuram and Cuddalore in the plaintiff-State.

2.4. In this context, the Chief Secretary of the plaintiff-State called upon the defendant-State to adhere to the Agreement of 1892, contending that, in terms thereof, no such works could have been undertaken by the defendant-State on the inter-State River without obtaining the prior consent of the plaintiff-State.

2.5. Subsequently, the plaintiff-State became aware that the defendant-State was proposing to construct check dams across a tributary of the River Pennaiyar. On 22nd May, 2013 when officials of the plaintiff-State conducted a field inspection of the site, they submitted a report recording that preliminary works relating to the construction of the dam had commenced, a fact which was further corroborated by the display board erected at the site.

2.6. Ultimately, vide communication dated 1st July, 2013, the defendant-State responded to the concerns raised by the plaintiff-State. In the said reply, the defendant-State asserted that the Agreement of 1892 was merely a political arrangement entered into in the prevailing regime of that period and had ceased to have effect upon the attainment of independence by the Union of India. On that premise, it was contended by the defendant-State that no consent of the lower riparian State, namely the plaintiff-State, was required.

2.7. Aggrieved by what is alleged to be the unilateral refusal of the defendant-State to comply with and act in accordance with the Agreement of 1892, the plaintiff-State approached this Court by instituting the present suit through a plaint dated 18th May,

2018. The pleadings stood completed upon the filing of the replication by the plaintiff-State on 7th May, 2019.

2.8. During the pendency of the present suit, the plaintiff-State filed an interlocutory application1, seeking, inter alia, the issuance of the following directions: -

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"a. restrain the defendant-State and its instrumentalities from proceeding further with the construction of dam across Markandeyanadhu near Yargol Village;

b. direct the defendant-State and its instrumentalities not to obstruct the natural flows to the downstream plaintiff-State pending the disposal of the present application."

2.9.

This Court, vide order dated 14th November, 2019, dismissed the said application and declined to grant any interim relief, primarily on the ground that nearly 75% of the construction work had already been completed by the defendant-State and that the material on record prima facie indicated that the project in question had been undertaken after obtaining all requisite sanctions and permissions. However, the plaintiff-State was granted liberty to move an appropriate application invoking the powers of the Central Government for the constitution of an Inter-State River Water Disputes Tribunal in accordance with the provisions of the Inter-State River Water Disputes Act, 1956.

2.10. On 30th November, 2019 the plaintiff-State lodged a complaint under Section 3 of the Inter-State River Water Disputes Act, 1956, calling upon the Central Government to constitute a Tribunal for the adjudication of the Pennaiyar River water dispute.

In pursuance thereof, the process for the constitution of an Inter- State River Water Disputes Tribunal commenced under the aegis of the Central Government. In the interregnum, the plaintiff-State filed a further application2 dated 16th December, 2019, before this Court, seeking a direction to the Central Government to constitute an Inter-State River Water Disputes Tribunal.

Upon the negotiation process having been undertaken and no amicable resolution having been arrived at between the parties, defendant no. 2 filed an affidavit dated 2nd January, 2025, before this Court, stating that: -

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"6. It is further submitted that this report is concluded that the Committee made sincere attempts to resolve the issue amicably between States of Tamil Nadu and Karnataka through discussions on multiple dates. The Committee has suggested some solutions to resolve the dispute.

However, in view of the firm stand taken by the Govt. of Tamil Nadu, no consensus could be reached between two States on solutions.

7. . . . it was decided, as a last effort, to organise a meeting of the Water Resource Ministers of both States to try and create a consensus on the solutions suggested by the Negotiation Committee. . . ."

Thus, negotiations in respect of the Pennaiyar River water dispute were initiated at the ministerial level. However, on 7th October, 2025 defendant no. 2, coordinating the negotiations between the plaintiff- State and the defendant-State, filed an additional affidavit before this Court stating that the earlier proposed meeting at the ministerial level had been postponed indefinitely. The relevant extract of the said affidavit reads as under: -

"5. . . . First meeting notice was issued to all party states for meting scheduled on 19.12.2024 at Ministers level but did not take place due to request of State of Karnataka to postpone the same as Winter Session of Karnataka Legislature Assembly was going during that period. . . .

6. It is submitted that as per tire direction of competent Authority, a preliminary meeting was held with the officials of party States under the Chairpersonship of Secretary (DoWR, RD&GR), on 03.03.2025. During the meeting, the Karnataka, reiterated that it has agreed for a total 15% release of water including 7.5% from Yargol dam and 7.5% from other tributary (Masti Sub-Basin), at the border, expressed interest to iron out any differences through negotiations. On the other hand, the Tamil Nadu stood to its position that a Tribunal be constituted for the resolution of dispute.

7. It is submitted that Second Meeting notice was issued to all party states for meeting scheduled on 18.03.2025

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at Ministers Level. However, the Tamil Nadu expressed an opinion that any further negotiation would only delay the constitution of the Tribunal and stated that there is no need for any further negotiation at the level of Hon'ble Minister of Water Resources of the States. Further, the State of Tamil Nadu has reiterated its stand for constitution of Tribunal to resolve the Pennaiyar Water Dispute vide its communication dated 15.03.2025. . . .

8. It is submitted that in view of the opinion and stand taken by the Tamil Nadu, the proposed meeting [on 18.03.2025] at Ministers level has been postponed indefinitely vide DOWR, RD&GR dated 17.03.2025. . . ."

(emphasis laid)

We have heard Mr. V. Krishnamurthy and Mr. P. Wilson, learned Senior counsel for the plaintiff-State of Tamil Nadu, Mr. Shyam Diwan and Mr. Mohan V. Katarki learned Senior counsel, along with Mr. Shashi Kiran Shetty, learned Advocate-General, appearing for the defendant-State of Karnataka and Ms. Aishwarya Bhati, learned Additional Solicitor General, appearing for defendant no. 2 - Union of India.

The present Pennaiyar River water dispute has been pending consideration before this Court since the year 2018. Multiple efforts have been undertaken by the concerned stakeholders to bring about an amicable resolution of the dispute. However, we have no hesitation in recording that the negotiation process has not yielded any mutually acceptable outcome. In view of the inability of the parties to arrive at a common settlement, we consider it appropriate to call upon the Central Government to constitute a Tribunal in terms of the statutory framework, so that the dispute may be adjudicated in accordance with law.

In addition, the affidavit dated 7th October, 2025, filed by defendant no. 2 elucidates the prevailing position on the ground with respect to the statutorily mandated negotiation process. The said affidavit records that, during the ministerial-level negotiations, the plaintiff- State unequivocally conveyed that the Pennaiyar River water dispute


ought to be resolved through adjudication by a Tribunal. It was in view of this firm stand adopted by the plaintiff-State that defendant no. 2 took a decision to indefinitely defer the negotiation process.

This Court, in T.N. Cauvery Neerppasana Vilaiporulgal Vivasayigal Nala Urimai Padhugappa Sangam v. Union of India,3 has held that where the statutorily prescribed negotiation process conducted under the aegis of the Central Government fails to bring about a resolution of an inter-State River water dispute, it becomes imperative for the Central Government to constitute a River Water Disputes Tribunal, and to refer the dispute for adjudication to such Tribunal. The Court accordingly observed as follows: -

"18. Section 4 indicates that on the basis of the request referred to in Section 3 of the Act, if Central Government is of the opinion that the water dispute cannot be settled by negotiation, it is mandatory for the Central Government to constitute a Tribunal for adjudication of the dispute. We were shown the Bill where in Section 4 the word 'may' was used. Parliament, however, substituted that word by 'shall' in the Act. Once we come to the conclusion that a stage has reached when the Central Government must be held to be of the opinion that the water dispute can no longer be settled by negotiation, it thus becomes its obligation to constitute a Tribunal and refer the dispute to it as stipulated under Section 4 of the Act. . . ."

(emphasis laid)

10. We, therefore, find no reason to refrain from directing the Central Government to issue an appropriate notification in the Official Gazette and to constitute a Water Disputes Tribunal for the adjudication of the inter se water dispute between the parties herein, within a period of one month from today.

11. We order as above.

12. With the aforesaid direction, the present suit stands disposed of.

(1990) 3 SCC 440

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13. Needless to mention that all questions, including those relating to the reliefs that may be available to the parties, are kept open for consideration by the Tribunal.

Result of the case: Suit disposed of.

†Headnotes prepared by: Nidhi Jain