The Tamil Nadu government on Wednesday wrote a letter to Prime Minister Narendra Modi, opposing the centre's nod to Kerala's proposal to conduct an Environmental Impact Assessment Study for construction of a new dam in place of the existing Mullaperiyar reservoir.
Opposition parties too hit out at the centre over the issue, with principal opposition party DMK urging the state government to file a case against the Environment Ministry.
In his letter, Chief Minister K Palaniswami said a committee under the Ministry of Environment, Forest and Climate Change had last month recommended for grant of Terms of Reference of Kerala's proposal to conduct the Environmental Impact Assessment Study for the construction of a new dam.
"This has caused great apprehension and consternation among the people of Tamil Nadu," he said, adding that the move violated the Supreme Court order on the issue over which the two states are locked in dispute.
Mr Palaniswami said the Expert Appraisal Committee for River Valley and Hydro Electric Projects had made the recommendation at a meeting on September 27.
The Kerala government approaching the centre on the issue and the latter entertaining it were "in gross violation of the decree" of the Supreme Court on the inter-state dispute, the chief minister said.
Quoting from the May 2014 court verdict, he said: "For the construction of a new dam, there has to be agreement of both the parties. The offer made by Kerala cannot be thrust upon Tamil Nadu."
He further said Kerala had in August 2014 "stealthily" obtained clearance for such a study for the construction of a new dam without informing or consulting Tamil Nadu or obtaining its concurrence on the matter.
This was "in utter defiance" of the court decree, he said and recalled that Tamil Nadu had to later issue a contempt notice against the member-secretary of the Standing Committee of the National Board for Wildlife and Wildlife Preservation Officer.
He drew PM Modi's attention to then Chief Minister J Jayalalithaa's letter to him in June 2015, seeking his intervention to instruct the Environment Ministry and its agencies to "desist from entertaining and considering" Kerala's proposal in future.
Following this, the centre had delisted Kerala's proposal in July 2015, he said.
Mr Palaniswami urged the prime minister to personally intervene and direct the Environment Ministry to forthwith withdraw the recommendations to grant Terms of Reference for the study.
The chief minister also requested PM Modi to direct the Environment Ministry to desist from entertaining any future proposal by Kerala on a new dam, and "also to negate the proposals which are in violation of the orders of the Supreme Court."
Opposition parties in the state, including DMK and MDMK, hit out the centre on the matter.
DMK Treasurer Durai Murugan it was "yet another attack" by the BJP-led Central government against Tamil Nadu.
The NDA was was repeatedly 'ignoring' Tamil Nadu's interests, he said.
Recommendation to grant Terms of Reference for the impact assessment study would also affect the harmony between Tamil Nadu and Kerala, he said in a statement.
A former PWD Minister, he said Centre's move amounted to "contempt of court" since the 2014 apex court verdict had said Tamil Nadu's concurrence was required for a new dam.
Expressing fears that a proposed dam could even spell danger for Kerala itself, "considering the recent natural disaster" (rains and floods), he said a possible new dam would affect irrigation prospects of five districts in Tamil Nadu also.
"The Palaniswami government should immediately file a case against the Central government and the Environment Ministry," he said in a statement.
The CPI (M)-led LDF government in Kerala should also drop the idea of a new dam, considering the welfare of the people and farmers of the two states, besides environmental concerns, he added.
MDMK founder Vaiko dubbed the Centre's action as a "betrayal" of the people of Tamil Nadu and charged Kerala with trying to go against the apex court verdict on the inter-state dispute.
He called for immediate revoking of the recommendation to grant Terms of Reference for Kerala's proposal.
PMK MP Anbumani Ramadoss also made a similar plea, while sidelined AIADMK leader and AMMK founder T T V Dhinakaran slammed both the Central and state governments on the issue.
He urged the state government to initiate legal action on this matter.
The centuries-old Mullaperiyar dam is located in the high range Idukki district of Kerala and is operated by Tamil Nadu under an inter-state agreement.
Kerala has been insisting on building a new dam, citing safety concerns of the existing structure.
In its May 2014 verdict, the top court had allowed Tamil Nadu to raise the storage at Mullaperiyar to 142 feet and ultimately to 152 feet after completing strengtheningmeasures on the dam.