The Ministry of Defence and DRDO have given nod to beginning of oil and gas hunt in 59 offshore areas. However, the clearance has come up with a condition that no permanent structures will be built above sea level.

As many as 77 blocks awarded since 1999 in various rounds of New Exploration Licensing Policy (NELP) to companies like ONGC, Cairn, Reliance Industries, BP and Australia's BHP Billiton were stuck for want of defence clearances as they either lay in path of Naval exercise zone or fall near the missile testing range.

When oil or gas is discovered, permanent structures like manned-platforms have to be built above sea to aid hydrocarbon production. However, this clearance is conditional to the companies not putting any permanent structure above the sea level, a pre-requisite which the explorers find difficult to abide by.