Constitution of India, 1950 — Art. 131—- Inter-State water dispute ~ Mullaperiyar dam, a masonry dam, constructed across Periyar river pursuant to lease agreement dated 29- 10-1886 executed between Government of the Maharaja of Travancore and the Secretary of State for india - On coming into force of the States Reorganisation Act, 1956, State of Travancore-Cochin was formed and State of Kerala is its’ successor-in-interest — State of Tamil Nadu is successor-in- interest of the Governor in Council, Secretary of State for India — Dam situated at Thekkady District in Kerala but owned and operated by the Government of Tamil Nadu — In an earlier round of litigation, vide judgment dated 27-2-2006, Supreme Court permitted water level in the Mullaperiyar dam to be raised up to 142 ft and also restrained the State of Kerala and its officers from causing any obstruction thereto — However, vide subsequent enactment of the 2006 Amendment Act by the Kerala State Legislature, Full Reservoir Level (FRL) of the dam fixed and limited to136 ft — Suit filed by State of Tamil Nadu u/Art. 131 of the Constitution against the State of Kerala ~ Maintainability of suit u/Art.131 - Validity and binding nature of 1886 L;ease Agreement and the effect of 1970 supplemental agreements — Held: Suit filed by State of Tamil Nadu was maintainable u/Art.131 of the Constitution — The suit was based on a legal right claimed under the lease deed dated 29-10-1886 — State of Kerala (first defendant) estopped from raising plea that lease deed dated 29-10-1886 had lapsed, in view of supplemental agreements dated 28-05- 1970 between State of Kerala and State of Tamil Nadu — Lease deed dated 29-10-1886 valid and binding on the first defendant (State of Kerala) and’enforceable against it - Kerala Irrigation and Water Conservation Act, 2003 — Kerala Irrigation and Water Conservation (Amendment) Act, 2006.

Constitution of India, 1950 — Art.131 — Inter-State water dispute — Mullaperiyar dam, a masonry dam, constructed across Periyar river — Dam situated at Thekkady District in Kerala but owned and operated by the Government of Tamil Nadu — In an earlier round of litigation, vide judgment dated 27-2-2006, Supreme Court permitted water level in the Mullaperiyar dam to be raised up to 142 ft and also restrained the State of Kerala and its officers from causing any obstruction thereto — However, vide subsequent enactment of the 2006 Amendment Act by the Kerala State Legislature, Full Reservoir Level (FRL) of the dam fixed and limited to 136 ft - Suit filed by State of Tamil Nadu u/Art. 131 of the Constitution against the State of Kerala - Whether 2006 Amendment Act unconstitutional and ultra vires, in its application to and effect on the Mullai Periyar Dam and whether judgment dated 27- 2-2006 operated as res judicata, in respect of all or any of the defences set up by the first defendant (State of Kerala) — Held: 2006 Amendment Act was unconstitutional and ultra vires in its application to and effect on the Mullaperiyar dam — Rights of Tamil Nadu, crystallized in judgment dated 27-2-2006 could not be nullified by a legislation made by the Kerala State legislature — Earlier judgment given on 27-2-2006 operated as res judicata on issue of the safety of Mullaperiyar dam for raising water level to 142 ft. - Kerala estopped from raising or re-agitating issues in the present suit — Kerala cannot obstruct Tamil Nadu from increasing the water level of Mullaperiyar dam to 142 ft. and from carrying out repair works as per judgment dated 27-2-2006 — Kerala Irrigation and Water Conservation Act, 2003 — Kerala Irrigation and Water Conservation (Amendment) Act, 2006 - Doctrines/Principles - Principle of res judicata and constructive res judicata - Applicability of

Constitution of India, 1950 — Art.131 — Inter-State water dispute — Mullaperiyar dam, a masonry dam, constructed across Periyar river - Dam situated at Thekkady District in Kerala but owned and operated by the Government of Tamil Nadu — In an earlier round of litigation, vide judgment dated 27-2-2006, Supreme Court permitted water level in the Mullaperiyar dam to be raised up to 142 ft and also restrained the State of Kerala and its officers from causing any obstruction thereto — However, vide subsequent enactment of the 2006 Amendment Act by the Kerala State Legislature, Full Reservoir Level (FRL) of the dam fixed and limited to 136 ft - Suit filed by State of Tamil Nadu u/Art. 131 of the Constitution against the State of Kerala — Whether first defendant (State of Kerala) estopped from contending that Periyar River is not an inter-State river — Held: it is true that averment of Tamil Nadu in the plaint that the two States — Kerala and Tamil Nadu — are riparian States is not right in its entirety because Tamil Nadu is not a riparian State but the status of Periyar river as inter-State river cannot be overlooked — It is not open to Kerala to take a totally inconsistent plea and begin fresh controversy about the status of Periyar river on the ground that the earlier plea was founded on some erroneous premise ~ Kerala cannot be permitted to contend that river Periyar is an intra-State river and not an inter-State river — Kerala Irrigation and Water Conservation Act, 2003 — Kerala Irrigation and Water Conservation (Amendment) Act, 2006 — Doctrines / Principles — Rule of estoppel. .

Constitution of India, 1950 - Art.131 — Inter-State water dispute — Mullaperiyar dam, a masonry dam, constructed across Periyar river - Dam situated at Thekkady District in Kerala but owned and operated by the Government of Tamil Nadu — In an earlier round of litigation, vide judgment dated 27-2-2006, Supreme Court permitted water level in the Mullaperiyar dam to be raised up to 142 ft and also restrained the State of Kerala and its officers from causing any obstruction thereto — However, vide subsequent enactment of the 2006 Amendment Act by the Kerala State Legislature, Full Reservoir Level (FRL) of the dam fixed and limited 0136 ft - Suit filed by State of Tamil Nadu u/Art. 131 of the Constitution against the State of Kerala — Whether offer of the first defendant (State of Kerala), to construct a new dam across River Periyar in the downstream region of Mullai Periyar Dam would meet the ends of justice and requirements of plaintiff — Held: For construction of new dam, there has to be agreement of both the parties — Offer made by Kerala cannot be thrusted upon Tamil Nadu - However, parties granted liberty to apply to the Court if they are able to arrive at some amicable solution — Kerala Irrigation and Water Conservation Act, 2003— Kerala Irrigation and Water Conservation (Amendment) Act,

Constitution of India, 1950 — Art:131 - Inter-State water - dispute — Mullaperiyar dam, a masonry dam, constructed across Periyar river ~ Dam situated at Thekkady District in Kerala but owned and operated by the Government of Tamil Nadu — In an earlier round of litigation, vide judgement dated 27-2-2006, Supreme Court permitted water level in the Mullaperiyar dam to be raised up to 142 ft and also restrained the State of Kerala and its officers from causing any obstruction thereto — However, vide subsequent enactment of the 2006 Amendment Act by the Kerala State Legislature, Full Reservoir Level (FRL) of the dam fixed and limited to 136 ft - Suit filed by State of Tamil Nadu u/Art. 131 of the Constitution against the State of Kerala — Whether plaintiff entitled to a permanent injunction restraining the first defendant (State of Kerala) from applying and enforcing the 2006 Amendment Act with reference to Mullai Periyar Dam — Held: On facts, Tamil Nadu able to establish that invasion on its rights. was substantial ~ Tamil Nadu able to make out a case for grant - of injunction -2006 Amendment Act passed by Kerala legislature unconstitutional in its application to and effect on the Mullaperiyar dam — -1st defendant (State of Kerala) restrained by decree of permanent injunction from applying and enforcing the impugned legislation or in any manner interfering with or obstructing the State of Tamil Nadu from increasing the water level to 142 ft. and from carrying out the repair works as per the judgment dated 27-2-2006 — To allay the apprehensions of Kerala about safety of Mullaperiyar dam on restoration of FRL to 142 ft, a 3-Member Supervisory Committee constituted -— Committee to have one representative from the Central Water Commission and one representative each from the two States of Tamil Nadu and Kerala — Kerala Irrigation and Water Conservation Act, 2003 — Kerala Irrigation and Water Conservation (Amendment) Act, 2006 — Suit - Suit for injunction.