After giving nod to the Oil and Natural Gas Commission, the Union Environment Ministry has accorded preliminary clearance to Vedanta Limited to drill 274 hydrocarbon exploratory wells, both offshore and onshore, in Tamil Nadu. 
Cairn Oil & Gas, a Vedanta vertical, had submitted two separate applications seeking Terms of Reference (ToR) for conducting Environment Impact Assessment (EIA) studies. Approval for drilling 158 wells in the Cauvery block — covering an area of 2,574 sq km consisting of 142 sq km of Nagapattinam, 39 sq km of Karaikal and 2,393 sq km of sea portion of the Bay of Bengal — was given on Sunday. 
Permission to drill 116 wells in a block covering an area of 1,794 sq.km (139 sq km of Viluppuram, 2sq km of Puducherry and 1,654 sq km of sea portion of Bay of Bengal) was given on May 10.