Back in May, Trump announced that he was withdrawing the US from a nuclear agreement brokered under President Obama in 2015 between Iran, the US, and five other countries. Trump wasn't satisfied with the treaty, which he felt didn't do enough to ensure Iran was curbing its nuclear program, and preferred to impose sanctions instead. The sanctions are due to go into effect on November 4, 2018 but they've already had an anticipatory restraining effect on the Iranian economy, with Iranian crude exports dropping. Even the five other countries who are still pledged to the 2015 on paper are abandoning Iran to seek other suppliers.
Still, there was some doubt as to whether the rest of the international community would abide by Trump's imposition of the sanctions. By the end of September, India - one of Iran's largest oil customers - had yet to put in orders for more oil for November, suggesting to some that India was going to cut Iranian imports and find another supplier in compliance with US sanctions.
But on October 5, 2018, state-owned Indian companies Indian Oil Corp (IOC) and Mangalore Refinery and Petrochemicals LTD (MRPL) signed a contract with Iran for the delivery of 1.25 million tons of crude oil from the Persian Gulf. India has said they hope to continue to import oil from Iran, albeit in somewhat reduced quantities.
It will be difficult for India to cut Iran completely from the picture. Iran is India's third-largest supplier, and India is Iran's number two top oil importer after China. Limiting oil imports to India will be an important part of ensuring the sanctions have their intended effect; as such, the US is considering issuing a sanction waiver in hopes of gradually weaning India off of Iranian supply. While IOC is importing at normal levels, other Indian companies like Nayara Energy and Reliance Industries have completely eliminated Iranian oil, or cut back drastically on the quantity received, in hopes of receiving such a waiver from the US.
Since US sanctions will block traditional Euro-based payment methods, India and Iran have discussed switching to an alternative, rupee-based payment mechanism. They may also trade goods such as wheat and soybeans for the oil.
- https://www.nytimes.com/2018/05/08/world/middleeast/trump-iran-nuclear-deal.html
- https://www.nytimes.com/2018/09/19/business/energy-environment/iran-oil-sanctions.html
- https://www.bloomberg.com/news/articles/2018-09-25/india-is-said-to-cut-imports-of-iranian-oil-to-zero-in-november-jmhy95z8?srnd=premium
- https://economictimes.indiatimes.com/industry/energy/oil-gas/india-to-continue-iranian-oil-imports-post-us-sanctions/articleshow/66088584.cms
- https://www.business-standard.com/article/current-affairs/us-mulls-waivers-on-iran-oil-sanctions-amid-india-s-refusal-to-stop-imports-118100600062_1.html