Full Judgment Text
REPORTABLE
2026 INSC 113
IN THE SUPREME COURT OF INDIA
CIVIL ORIGINAL JURISDICTION
ORIGINAL SUIT NO. 1 OF 2018
THE STATE OF TAMIL NADU …PLAINTIFF(S)
VERSUS
THE STATE OF KARNATAKA & ANR. …DEFENDANT(S)
J U D G M E N T
VIKRAM NATH, J.
1. 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;
Signature Not Verified
Digitally signed by
NEETU KHAJURIA
Date: 2026.02.03
18:47:11 IST
Reason:
O.S. NO.1 OF 2018 1
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;
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.
2. 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
O.S. NO.1 OF 2018 2
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
O.S. NO.1 OF 2018 3
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
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across a tributary of the River Pennaiyar. On 22 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.
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2.6. Ultimately, vide communication dated 1 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
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suit through a plaint dated 18 May, 2018. The
O.S. NO.1 OF 2018 4
pleadings stood completed upon the filing of the
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replication by the plaintiff-State on 7 May, 2019.
2.8. During the pendency of the present suit, the plaintiff-
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State filed an interlocutory application , seeking, inter
, the issuance of the following directions: -
alia
“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.”
th
2.9. This Court, vide order dated 14 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.
th
2.10. On 30 November, 2019 the plaintiff-State lodged a
complaint under Section 3 of the Inter-State River Water
Disputes Act, 1956, calling upon the Central
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I.A. No. 95384 of 2019
O.S. NO.1 OF 2018 5
Government to constitute a Tribunal for the adjudication
of the Pennaiyar River water dispute.
3. 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,
2 th
the plaintiff-State filed a further application dated 16
December, 2019, before this Court, seeking a direction to the
Central Government to constitute an Inter-State River Water
Disputes Tribunal.
4. Upon the negotiation process having been undertaken
and no amicable resolution having been arrived at between the
nd
parties, defendant no. 2 filed an affidavit dated 2 January,
2025, before this Court, stating that: -
“ 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. . . . ”
5. Thus, negotiations in respect of the Pennaiyar River water
th
dispute were initiated at the ministerial level. However, on 7
October, 2025 defendant no. 2, coordinating the negotiations
between the plaintiff-State and the defendant-State, filed an
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I.A. No. 193417 of 2019
O.S. NO.1 OF 2018 6
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 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 . . . .
It is submitted that in view of the opinion and stand
8.
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)
6. 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
O.S. NO.1 OF 2018 7
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.
7. 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.
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8. In addition, the affidavit dated 7 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.
9. This Court, in T.N. Cauvery Neerppasana
Vilaiporulgal Vivasayigal Nala Urimai Padhugappa
O.S. NO.1 OF 2018 8
3
Sangam v. Union of India , 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.
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(1990) 3 SCC 440
O.S. NO.1 OF 2018 9
12. With the aforesaid direction, the present suit stands
disposed of.
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.
.......................................J.
[VIKRAM NATH]
.......................................J.
[N. V. ANJARIA]
NEW DELHI;
FEBRUARY 02, 2026
O.S. NO.1 OF 2018 10