Press Trust of India. Despite the introduction of CNG almost two years ago in an attempt to improve the capital’s air, nitrogen dioxide levels in Delhi are rising.

Although levels of sulfur dioxide (SO₂) have dropped, nitrogen dioxide (NO₂) levels have increased some 20% at peak since 2002, raising the possibility of increased health hazards for residents.

According to the study, the level of NO₂ concentration in the ITO intersection in the city ranged from 70 to 102 microgram per cubic metre in the first week of February this year, whereas the standard limit is 80 microgram per cubic metre. During the same period in 2002, this figure ranged from 72 to 85 microgram per cubic metre.

“The primary reasons for the increase in the levels of NO₂ are the increase in the number of vehicles in Delhi and the emissions from the industrial units. Poor maintenance of the CNG vehicles is another factor contributing to the increase in NO₂ levels”, says Anumita Roychowdhury, Associate Director, Centre for Science and Environment (CSE).

Separately, a report released by the Eureka Forbes Institute of Environment in January found that Ahmedabad, the sixth-largest city in India, remains India’s worst-polluted city, again despite measures taken.

The Eureka Forbes study measured levels of suspended particulate matter (SPM), sulphur dioxide (SO₂), and oxides of nitrogen (NO_x) in ten cities for over one week. SPM levels in Ahmedabad were highest on eight days. The worst was on January 23, with SPM at 599 micrograms per cubic metre of air. On that day, Kolkata [Calcutta] was next worse-off with SPM at 329 micrograms per cubic metre.

Compare that to the EU-mandated PM limits of 50 µg per m³—a difference of an order of magnitude. 

...the figures show that the Air Action Plan, launched in November 2003, has come to naught—there’s no improvement at all.