NEW DELHI, September 3: The Association of Indian Automobile Manufacturers Association today reiterated that vehicles not fitted with catalytic converters can safely make a transition to unleaded petrol. With the compulsory shift to unleaded fuel, owners of cars without converters are still not convinced that their vehicles will come to no harm. However, the association has given an assurance that its use will neither reduce engine life nor it will cause `knocking' in old vehicles. The `green fuel' is available at the same price as leaded petrol at petrol stations across the Capital.Vehicle manufacturers endorsed Delhi's shift to unleaded petrol, saying that this would go a long way in improving engine life and controlling emissions.The association also rejected the common belief that use of unleaded petrol without a catalytic convertor would increase benzene emission. The ratio of benzene is the same in leaded and unleaded fuel and less lead does not automatically imply more benzene content in the fuel.The association pointed out that vehicles in eastern India have been using petrol with a low-lead content from the the Bongaigoan refinery for years with no signs of valve seat pitting or any other damage. ``Unleaded petrol does not increase benzene emission or even carbon monoxide and hydrocarbon emissions. On the contrary, it reduces engine rusting, piston ring wear and to a lesser degree sludge and varnish deposits,'' the association's technical committee chairman and director (engineering) Maruti Udyog Limited K. Kumar told newspersons.Kumar, however, advocates that vehicle owners should eventually install catalytic convertors in addition to ULP to significantly lower benzene emission. ``The convertors are necessary to convert benzene to carbon dioxide and water and also reduce carbon monoxide and hydrocarbon emissions,'' he said.The combination of unleaded fuel and catalytic converter will lead to the least vehicular emission, the association said.Moreover, availability of unleaded petrol has been assured by the year 2000 all over the country. Japan and Brazil switched to 100 per cent unleaded petrol way back in the 1980s, Canada phased out leaded petrol in 1990, Guatemala and Columbia in the early 1990s, Austria, Korea and Sweden in 1993, and the USA and Thailand made the transition in 1995. Taiwan would follow suit by January 2000.Kumar said that the shift to unleaded petrol was necessary, as leaded petrol accounts for 90 per cent of atmospheric lead, thus causing serious health hazards such as blood-related disorders. It acts as a neurotoxin, especially in children, he warned.