Iran is India's third-largest oil supplier after Iraq and Saudi Arabia. Iran supplied 18.4 million tonnes of crude oil between April 2017 and January 2018 (first 10 months of fiscal 2017-18)
India has boosted oil purchases, with much of the extra apparently going into storage at Mangalore. This may be temporary, though, if refiners are building stockpiles ahead of anticipated shortages
Cutting imports may affect India's current account and fiscal deficits, as sweet-grade Brent crude makes up 28% of its import basket; continued dealings with Iran may invite US sanctions