Seismic sources claim that the total acreage of the planned 3D seismic survey is still unclear, as many areas in the Mumbai basin might still be restricted by the Indian ­defence ministry.

“We have heard that the defence clearance for the Mumbai basin area is supposed to be only partial,” said a seismic source.

BHP operates 10 offshore blocks in the Mumbai and ­Kerala-Konkan basins.

BHP