Terming as ‘unilaterial and shocking’ Centre’s nod to Kerala to undertake a survey for constructing a new dam across inter-state Mullaperiyar river, Tamil Nadu unit of the Congress requested Prime Minister Manmohan Singh to intervene and revoke the permission.

In a letter to Dr. Singh, the TNCC president K V Thangkabalu asked him to instruct Union Environment and Forest Ministry headed by Jairam Ramesh, to keep off the issue till the Supreme Court gave its verdict on a pending case relating to the dispute between upstream Kerala and Tamil Nadu over water storage level in the existing century-old dam in Idukki District.

“Only talks (moderated by the Centre) between the Chief Ministers of the two states can solve this emotive issue.

Instead of doing that, the Union Environment Ministry gave a unilateral nod to Kerala to undertake the survey which is shocking and regrettable,” he said.

Water from the Mullaperiyar was crucial for farmers in six downstream districts in the state, Mr. Thangkabalu said.

“Prime Minister Manmohan Singh should immediately intervene and revoke the permission given by the Environment and Forest Ministry to Kerala. He should also instruct the Ministry to keep off the issue till talks resolved the issue or the Supreme Court gave its verdict,” he said.

The Chief Minister M Karunanidhi had on Monday assailed the Centre for according permission for the survey without consulting Tamil Nadu and said the state would move the Supreme Court to obtain a stay to stall it.