The government's income from Cairn India's Barmer field is estimated to fall 9 per cent to Rs 52,757 crore (Rs 527.57 billion) after the royalty from the block is made cost-recoverable.
This is one of the conditions the government has put to clear Vedanta Resources' deal to buy a majority stake in Cairn India.
The government's income from a gas/oil block is known as profit petroleum.
"The government's share of profit petroleum is estimated to fall by about Rs 5,000 crore (Rs 50 billion) if the royalty is made cost-recoverable," said a senior government official.
He, however, added that if the entire royalty was paid by ONGC, Cairn's partner in the Barmer block, the government would have had to reimburse the full amount, incurring an expenditure of Rs 12,600 crore (Rs 126 billion).
"In a way, this is a saving for the government," he said.
While making a case for approval to the deal, Cairn had time and again impressed upon the government that making the royalty payment cost-recoverable would hit it hard as the amount went to the state government. The Centre got its share in the form of profit petroleum.
While ONGC, as a licensee, was obliged to bear the full royalty burden, the accounting procedure in the production sharing contract said the royalty paid by ONGC was cost-recoverable