With western sanctions on Iran lifted now, the country wants to do away with middlemen and sell crude directly to buyers like India. The state-owned National Iranian Oil Company (NIOC) has communicated to Indian refiners about it.

"It has recently come to our knowledge that Iranian crude oil has been offered to some Indian customers through some parties rather than National Iranian Oil Company," wrote Seyed Mohsen Ghamsari, the director for international affairs at NIOC, according to Reuters, which claimed to have seen the letter.

"In this respect, we hereby would like to inform you that ... National Iranian Oil Company has the sole right to market and sell Iranian crude oil and this right is not granted to any other parties for (the) Indian market," the 13 January letter further said.

The company also said that it applies to all buyers worldwide.

Reuters quoted Indian refining sources as saying that they had initiated talks with a Russian firm, Promsi, during mid-2015 to buy Iranian crude, though NIOC did not sell any oil after having agreed to do so through the Russian firm.

Meanwhile, NIOC said that it is committed to pump an additional 500,000 barrels per day, now that the sanctions have been lifted. 

"We have not moderated our plans regarding increasing output when sanctions are lifted. It will be increased by 500,000 bpd, and by another 500,000 bpd shortly after that," Mehdi Assali, Iran's national representative to the Organization of the Petroleum Exporting Countries (OPEC), had said on 17 January, 2016. 

The Persian country's current production is around 2 million barrels per day. When the sanctions were still in place over its nuclear weapons programme, Iran was allowed to export only half of it.

Besides buying crude oil, India and Iran have committed to increase bilateral trade in many areas. At the 18th session of the India-Iran Joint Commission held in New Delhi on 28 December, 2015, Indian External Affairs Minister Sushma Swaraj and Iran's Minister of Economic Affairs and Finance Ali Tayebnia expressed a desire to expand bilateral economic cooperation in energy, infrastructure, including shipping, ports and railways.

India is the second biggest buyer of Iranian oil after China.