A leaking tank from a sunken ship has caused an oil slick off India''s western coast, according to a defence ministry statement. The leak occurred in the merchant ship MV Rak which sank near the Mumbai coast last Thursday, the statement said. Coast guard ships have been deployed to clean up the eight mile-long slick, according to the (BBC). The vessel was carrying a cargo of coal and was travelling from Indonesia to the western Indian state of Gujarat. Indian navy and coast guard helicopters rescued the 30 crew members before the ship sank. The MV Rak sank about 23 miles from the Mumbai coast last Thursday. "Since Saturday night, oil has been observed leaking from the sunken vessel at an approximate rate of 1.5 to 2 tonnes per hour. The oil has spread to about seven nautical miles [eight miles] around the vessel," the defence ministry release said. The vessel reportedly contained some 340 tonnes of fuel.