new delhi compressed natural gas cng is no better than ultra low sulphur diesel as automotive fuel a study conducted by the indian institute of technologydelhi has found contrary to popular perception cng vehicles emit more carbon monoxide co and nitrogen oxide no than those running on 005 per cent ultra low sulphur diesel run euroii automobiles says the study commissioned by indianoil corporation use of cng does reduce particulate matter pm emissions but increases co and hydrocarbon emissions from buses prof dinesh mohan of iitdelhi who was part of the study team said while releasing the report on thursday during the study traffic flow measurements at vikas marg nanak pura and aiims crossing showed no major differences in total emission based on present traffic mix whether all buses use cng all buses use euroii engines or the mix is half and half according to the assessment of the impact of the changeover to cng a five per cent shift from buses to two wheelers on account of higher fares co emission goes up by about 18 per cent and hydrocarbon emission by up to 25 per cent the particulate matter emission shows an increase of about 15 per cent against this the relative decrease in nitrous gases was found to be 26 per cent referring to the cng versus diesel row prof mohan said there was no such thing as a clean fuel all fossil fuels cause pollution the government should not specify particular fuels or technology for use as such measures encourage monopolies and discourage technology innovation prof mohan said the government should only set emission standards and see to it that these are strictly followed he said prof mohan said the proportion of cars in the union capital has been rising at the rate of 10 per cent a year while twowheelers have been rising at 70 per cent twowheelers and buses are comparable contributors to particulate emissions and hence any strategy for reducing pollution must target both he said