India's imports of Russian oil rose tenfold last year, according to Indian state-controlled lender Bank of Baroda.
The figures show Asia's third largest economy saved around $5bn (£4bn) as it ramped up crude purchases from Moscow.
It comes as Western countries have been cutting their imports of energy from Russia after its invasion of Ukraine.
Russia has been selling energy at a discount to countries like China and India, which is the world's third largest importer of oil.
In 2021 Russian oil accounted for just 2% of India's annual crude imports. That figure now stands at almost 20%, Bank of Baroda said.
India's purchases of oil from Russia during the last financial year, saved it around $89 per tonne of crude, the figures show.
Despite pressure from the US and Europe, India has refused to adhere to Western sanctions on Russian imports. New Delhi has also not explicitly condemned Russia's invasion of Ukraine.
India has defended its oil purchases, saying that as a country reliant on energy imports and with millions living in poverty, it was not in a position to pay higher prices.
Since the Ukraine war began, Europe had imported six times more energy from Russia than India, the country's External Affairs Minister S. Jaishankar said in a TV interview last year.
"Europe has managed to reduce its imports while doing it in a manner that is comfortable," he said.
Mr Jaishankar added: "If it is a matter of principle why did Europe not cut on the first day?"
With no end in sight to the conflict, some analysts expect Russia to continue to offer cheap oil to Asia's biggest energy importers.
"We expect Russian crude intake to remain limited to these two countries [India and China], sustaining the steep discounts," Vandana Hari, from energy analysis firm Vanda Insights told the BBC.
India's oil refiners will continue to maximise their profit margins for as long as they can, but will simply "go back to their usual crude diet" if the sanctions were to be lifted, she added.
BDST: 1219 HRS, MAY 11, 2023