NO2 levels in Delhi, UP far exceed CPCB safe limits

Despite policies measures such as EV policies, metro network, BS-VI fuel, scrapping vehicles older than 15 years etc, to control vehicular emissions in cities like Delhi, the national capital has not been able to meet CPCB's annual NO2 average even once since 2013.

And unfortunately, Delhi is not the only city in northwest India with this dubious distinction as an analysis of the trends for nitrogen dioxide (NO2) for three states in northwest India - Delhi, Uttar Pradesh, and Rajasthan - breached the Central Pollution Control Board (CPCB) safety limits in November 2021.

An analysis by NCAP Tracker, an air pollution policy tracking platform, has shown that between 2013 and 2020, Delhi hasn't experienced a single year where NO2 annual average was within safety limits even as despite the nationwide lockdown in 2020, Delhi's annual NO2 average for the year remained at 61 micrograms per metre cubed.

Emerging as a new cause of worry, NO2 levels were 73.66 and 71 in 2018 and 2019 respectively, showed the analysis that did a deep dive into the non-attainment cities in all three states, CAAQMS monitoring sites, annual NO2 trends, number of days when daily NO2 averages were breached at each monitoring site, along with an analysis for the trends, a statement from Climate Trends, an advocacy think tank, that has launched the NCAP tracker platform, said.

That is not all. At 15 out of 40 monitoring sites in Delhi, the daily average for NO2 was above 80 micrograms per metre cubed for the month of November 2021, while as many as 25 out of the 40 sites experienced anywhere between 1-30 days when levels crossed the daily average of 80 micrograms per metre cubed, and 18 sites recorded annual averages above the 40 micrograms per metre cubed safety limit for NO2 set by the CPCB.

WHO limits annual NO2 average at 10 micrograms per metre cubed and daily at 25 microgram per metre cubed.

Similarly, out of 17 cities in Uttar Pradesh, 11 breached annual NO2 average set by CPCB at 40 micrograms per metre cubed. These cities are Varanasi (41), Noida (57), Muzaffarnagar (52), Meerut (59), Lucknow (58), Kanpur (62), Greater Noida (65), Ghaziabad (70), Firozabad (47), Bulandshahr (59), and Baghpat (60).

There are just 10 monitoring sites for the eight cities in Rajasthan. Five of these locations experienced days where NO2 levels crossed daily averages - RIICO Industrial Area, Bhiwadi (six days), Police Commissionerate, Jaipur (23 days), Adarsh Nagar, Jaipur (seven days), Collectorate, Jodhpur (11 days) and Ashok Nagar Udaipur (one day).

Only the capital city, Jaipur has three monitoring sites while all other cities have one CAAQMS monitor each.

Director, National Institute for Implementation Research for Non-Communicable Diseases (under the ICMR), Dr Arun Sharma, said: "NO2 as a gas has not so serious effects on the health of the people, but it's secondary effects through increase in PM2.5 concentrations and augmentation of Ozone formation are a matter of concern. The average NO2 concentration is higher than the CPCB prescribed limit for all these cities in November 2021. The only way that the NO2 levels can be controlled are by reduction at source, as fixation of NO2 in the air along with SO2 is cause for acid rain."