New Delhi: India’s capital is rapidly losing out on the gains it made in terms of improved air quality from the mandatory use of Compressed Natural Gas (CNG) for public transport vehicles, because of a rise in the number of diesel vehicles.

“This year, we had widened our pollution monitoring activity across Delhi and we found a significant increase in particulate matter. The rise in diesel vehicles is chiefly responsible for this state of affairs,” said J.K. Dadoo, chairperson, Delhi Pollution Control Committee.

Dadoo was speaking at a discussion organized by environmental activist group, Centre for Science and Environment (CSE).

At the Monday meeting, which included representatives of automobile companies, Sunita Narain, the head of CSE, said there ought to be a strong policy to disincentivize diesel to prevent the “threatening increase in nitrogen oxide emissions and RSPM (respiratory suspended particulate matter) in the last few years”.

Although diesel vehicles cost more than the corresponding petrol variants, diesel in New Delhi costs around 30% less than petrol.

Narain added that unless clean diesel was introduced, the government would do better to “ban diesel vehicles in health interest”.

Ravi Kant, managing director of Tata Motors Ltd, one of the country’s largest manufacturers of diesel cars, was present at the meeting, but did not respond to thie suggestion.

“We’ve never been against fuel standards and we are forever open to discussion regarding use of technology to check particulate emissions,” said Dilip Chenoy, director general, Society of Indian Automobile Manufacturers, an industry body.

CSE recently released a study that claimed concentrations of suspended particulate matter had significantly increased in New Delhi since 2006.