Environmentalists have criticised the government of Delhi's attempts to get diesel with a 0.05% sulphur content accepted as a clean fuel. They say the move is designed to placate the transport lobby. The Centre for Science and Environment (CSE) - an Indian environmental NGOs specialising in sustainable natural resource management - says the Delhi Government is trying to dilute the July 1998 Indian Supreme Court directive on clean fuel. The Delhi government wants the Supreme Court to recognise 0.05% sulphur diesel as a clean fuel. This proposition, warns the CSE, will defeat the whole purpose of the Supreme Court order, which requires the replacement of all pre-1990 rickshaws and taxis with new vehicles that run on compressed natural gas (CNG) by March 31, 2000.