CPI (M) Polit Bureau has said that the decision of the Centre to bar Indian companies from using the Asian Clearing Union, ACU, to process payments will directly affect India's trade with Iran. In a statement, the party alleged that the Americans have been pressurizing India to close down this route as they consider it a barrier in the implementation of the US's arbitrarily imposed sanctions on all companies doing trade with Iran. Iran constitutes around 16 to 17 per cent of the country's crude oil requirements. It is also the largest trading partner of India in the ACU.