Oil companies yesterday came under pressure to explain their pricing policy for environmentally friendlier diesel after it was revealed they were making up to 45 cents a litre in extra profits at taxpayers' expense. Transport groups, the Consumer Council and the Government demanded an explanation from the firms on the price of ultra-low-sulphur diesel, imported for the first time in July. The Government having agreed to give the oil companies a tax concession of 89 cents a litre to persuade drivers to use the cleaner fuel, it later emerged that the diesel was only 40 to 46 cents more expensive. The firms have not reduced the price accordingly. The Hong Kong, Kowloon and New Territories Public & Maxicab Light Bus Merchants' United Association said many of its members felt cheated. 'We think the fuel price should be reduced immediately and the oil firms must refund any extra fuel charges to their regular customers if they are honest enough,' said chairman Leung Hung. The Consumer Council said it understood the users' concerns but was in no position to take any practical action. 'It will be impossible to get to the bottom of this because we have no powers to force them to disclose the information,' spokesman Kenneth So Wai-sang said. The Economic Bureau said its officials had met oil companies to talk about the issue. 'During the meeting, we asked them to account for the alleged price differential and to give the consumers a clear and convincing explanation,' a spokesman said. Transport industry lawmaker Miriam Lau Kin-yee asked oil firms to refund money pocketed from government subsidies. 'The oil companies should reduce the retail price of the fuel immediately. The community feels cheated.' Caltex, Shell, Exxon Mobil and China Resources Petroleum did not reply to requests for comment. The director of the Hong Kong Energy Studies Centre at Baptist University, Dr Larry Chow Chuen-Ho, said the controversy could have been avoided if the authorities had set a fixed introductory price for the fuel. '. . . I feel the Government should have thought more thoroughly about the details,' he said. In July, the import price of the fuel was $2.08 a litre compared with conventional diesel at $1.64 a litre, giving a profit of 45 cents. Sixteen million litres of the more expensive fuel were imported that month. In August, the import prices were, respectively, $2.27 and $1.81 with 130 million litres bought.