Half of these funds would be earmarked for settling payments for exports of Indian goods to Iran, they said.
India had won the exemption after it agreed to cut imports and escrow payments.
Under the 180-day exemption, India is allowed to import a maximum of 300,000 barrels a day of crude oil. This compares to an average daily import of about 560,000 barrels this year.
India, which is the second biggest purchaser of Iranian oil after China, has since then restricted its monthly purchase to 1.25 million tonne or 15 million tonne in a year (300,000 barrels per day), down from 22.6 million tonne (452,000 barrels per day) bought in 2017-18 financial year, sources said.
India, the world's third biggest oil consumer, meets more than 80 per cent of its oil needs through imports. Iran is its third largest supplier after Iraq and Saudi Arabia and meets about 10 per cent of total needs.
US President Donald Trump in May withdrew from the 2015 nuclear accord with Iran, re-imposing economic sanctions on the Persian Gulf nation. Some sanctions took effect from August 6, while those affecting the oil and banking sectors will start from November 5.
During the first round of sanctions when EU joined the US in imposing financial restrictions, India initially used a Turkish bank to pay Iran for the oil it bought. Beginning February 2013, India paid 45 per cent of the oil import bill in rupees while keeping the remainder pending till the opening of payment routes. It began clearing the dues in 2015 when the restrictions were eased.
Sources said New Delhi may export goods, including wheat, soybean meal and consumer products, to Iran during the exemption period.
Iran was the India's second biggest supplier of crude oil after Saudi Arabia till 2010-11 but Western sanctions over the Persian Gulf nation's suspected nuclear programme relegated it to the seventh spot in the subsequent years. In 2013-14 and 2014-15, India bought 11 million tonne and 10.95 million tonne crude, respectively from Iran.
Sourcing from Iran increased to 12.7 million tonne in 2015-16, giving it the sixth spot. In the following year, the Iranian supplies jumped to 27.2 million tonne to catapult it to the third spot.
Iranian oil is a lucrative buy for refiners as the Persian Gulf nation provides 60 days of credit for purchases, terms not available from suppliers of substitute crudes -- Saudi Arabia, Kuwait, Iraq, Nigeria and the US.
Besides blocking of banking channels from November, shipping firms are unwilling to transport Iranian oil. To get around this, Iran is using its own ships to transport crude to India. Its insurance companies are also providing insurance cover for such shipments, sources added.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)