Environment minister Jairam Ramesh had blamed subsidised diesel for causing air pollution but his own ministry had given it a clean chit saying major cause of ambient pollution in cities was roadside dust and cooking gas, not vehicles, the Centre for Science and Environment (CSE) claimed on Tuesday.
The CSE, which analysed the ministry’s Source Appropriation Study in six cities, said the study was a victim of bad science and damaging politics.
"The auto industry and the oil companies have begun to use the study results selectively to prove that vehicles are not the problem and diesel vehicles are even lesser," CSE associate director Anumita Roy Choudhury said.
One serious flaw pointed out was related to a study done in Delhi and Mumbai by the National Environmental Engineering Research Institute (NEERI) for the ministry.
In Delhi, the study attributed LPG used for domestic cooking as a source for about half of particulate matter of 2.5 microns (PM 2.5) but in case of PM of 10 microns no LPG presence was found.
The PM 2.5 finding for Mumbai is missing from the report. That's not all. The NEERI studies for two metros show vehicles to be the lowest for emissions of nitrogen oxides (NOx), whose primary source is diesel, and instead, blame power plants for high air pollution.
The study, first reported by HT, by air pollution experts from different institutes and then peer reviewed by international experts was finally vetted by officials from the environment and petroleum ministries, before made public. It is, however, not known whether the officials from the two ministries got any changes done. The study was being used as a scientific input for framing auto fuel policy for 2020.
"The NEERI study for Delhi and Mumbai grossly underestimates vehicles' contribution to both PM10, PM2.5 and NOx compared to other cities," Choudhury said.