Government officials told Business Standard that the environment ministry would vet the proposals for individual bidders during the current round.

"Certain areas like wildlife sanctuaries and water bodies with coral reefs are a strict no as far as we are concerned," an official in the ministry of environment and forests said.

For subsequent rounds, the environment and forests ministry has, however, asked the petroleum ministry to prepare an ecological map of India and list out areas where oil blocks will not be awarded due to environmental concerns. The information on these zones is proposed to be made available at the time of calling of bids.

"Under the present rules there is an element of uncertainty in the minds of the prospective investor. Once the information is available upfront it will be simpler for the investor to decide if it wants to bid and this will result in more investment," the environment and forest ministry official said.

In the previous four rounds of exploration licence auctions, the government signed 90 contracts involving an investment commitment of $4.4 billion.

Petroleum ministry officials said clearance had been received in principle but they were awaiting formal communication from the environment and forests ministry. In the next stage, the government will issue notices inviting tenders.

The government is also considering restricting the participation from companies located in certain sensitive countries.

In addition, conditions like deposit of dues in escrow accounts are expected to be put in place. A similar approach was adopted in the previous rounds.