The Text of the D.O. Letter dated 28.7.2026, addressed to the Hon'ble Prime Minister of India Thiru. Narendra Modi, from the Hon'ble Chief Minister of Tamil Nadu Thiru. C. Joseph Vijay, regarding Mekedatu Dam I wish to draw your kind attention to the reply in the Rajya Sabha by the Hon'ble Minister of State for Jal Shakti with regard to Mekedatu Dam, where the Hon'ble Minister has stated that the judgment of the Hon'ble Supreme Court dated 16 February 2018 does not expressly stipulate that Karnataka should obtain the consent of the lower riparian States before constructing a structure across the River Cauvery. This disappointing reply from the Hon'ble Minister of State for Jal Shakti seems to have been made without taking into consideration the prevailing legal position and settled law with regard to the consent of the lower riparian states. In this context, I bring to your kind notice the decision of the Constitution Bench of the Hon'ble Supreme Court in the Almatti case between the State of Karnataka and the State of Andhra Pradesh, wherein it was ruled that the consent of the lower riparian state is absolutely necessary. The relevant paragraph of the judgment in State of Karnataka Vs State of AP [2000(9) SCC, page 572], at paragraph 100, is extracted below: "100…nor can Karnataka State be permitted to construct up to that height without the consent of all other riparian States as well as without the approval of the Central Government…." As far as the Cauvery Tribunal Award is concerned, the Hon'ble Supreme Court expressly affirmed Clause XVIII of the Tribunal Award, which preserves the power of each State to regulate waters within its territory only "in a manner not inconsistent with the order of the Tribunal." Thus, any project that has the potential to affect the regulated flow regime established under the Award necessarily requires scrutiny for consistency with the Award. The Tribunal itself has laid down important guiding principles. In the case of Kerala's Pambar Hydro-electric Project, involving only 0.1 TMC of consumptive use, it directed that Kerala and Tamil Nadu should jointly agree upon the schedule of releases so that downstream irrigation is not adversely affected. This demonstrates that the Tribunal attached paramount importance not merely to annual quantities but also to coordinated regulation of releases affecting lower riparian interests. Further, Clause XI of the Award specifically prohibits any upper riparian State from taking action affecting scheduled deliveries to downstream States except through mutual agreement and consultation with the regulatory authority. Clause XX similarly recognises that modifications of the Award can only be achieved through agreement among the party States. Tamil Nadu is therefore of the considered opinion that the proposed Mekedatu Project cannot be evaluated merely as an engineering proposal. Its legal permissibility must first be examined in the context of: • the Final Award of the Cauvery Water Disputes Tribunal; • the judgment of the Hon'ble Supreme Court dated 16 February 2018; • the rights of the lower riparian States; and it is pertinent that the Detailed Project Report submitted by Karnataka in 2019 was returned by the Central Water Commission for revision to ensure compliance with the Tribunal Award and applicable guidelines. This itself demonstrates that compliance with the Award remains an indispensable precondition. In these circumstances, I earnestly request the Government of India to ensure that: The reply given by the Hon'ble Minister of State for Jal Shakti with regard to Unstarred Question No. 876 in the Rajya Sabha dated 27th July 2026, without referring to the settled law and legal principles in inter-state water issues, may be withdrawn. It is further to be ensured that: i. No statutory or administrative approval is granted to the Mekedatu Project unless it is demonstrably consistent with the CWDT Award and the judgment of the Hon'ble Supreme Court. ii. The rights of the lower riparian States in relation to both quantum and regulated pattern of releases are fully protected. iii. Any future consideration of the project shall be undertaken only after comprehensive technical and legal examination, taking into account the concerns of all lower riparian States. The River Cauvery is not merely a source of water but the lifeline of millions of farmers and citizens across southern India. Protecting the integrity of the Tribunal Award and the judgment of the Hon'ble Supreme Court is essential for maintaining confidence in the constitutional mechanism governing inter-State rivers. I request your kind intervention in the larger interest of justice, federal harmony and faithful implementation of judicial decisions. Issued by: Director, Directorate of Information and Public Relations, Chennai-9