The Centre has given permission only for survey and investigation of construction of Mullaperiyar dam in Kerala, which in no means would affect any other clearances required by it, Union Environment Minister Jairam Ramesh said on Tuesday.

“After consideration of the proposal, the Standing Committee of the National Board for Wildlife last month, in discharge of its statutory functions, decided to accord permission for survey and investigation (for the dam).

This permission is only for survey and investigation without in any way affecting any other legal and administrative clearances required,” the Environment Minister said in a statement here.

Mr. Ramesh’s observation comes a day after the Tamil Nadu Chief Minister M Karunanidhi opposed the Board’s decision saying that the issue was sub-judice and the ministry should have first consulted his government before issuing any direction in the matter.

Mr. Karunanidhi had also threatened to move Supreme Court to seek stay of the Ministry’s decision.

The construction of a new dam had been a longstanding demand of Kerala as it says the existing dam is weak and poses a hazard to thousands of people in the central part of the state.