Winter pollution shows rise in most Indian cities, says CSE

Heavy smog and air pollution near Ambattur Industrial Estate in Chennai in Tamil Nadu.   | Photo Credit: Vedhan M

The levels of PM 2.5, the most threatening of particulate matter, worsened in 43 out of 99 cities whose winter air in two years, 2020 and 2019, was compared by the Centre for Science and Environment (CSE). Only 19 registered “substantial improvement” — and one of these was Chennai. The restof the cities did not experience significant change.

In the aftermath of the lockdown, several cities reported improved pollution levels but by winter, when lockdowns were significantly eased, pollution levels had clawed back to pre-COVID-19 levels, the CSE notes, underlining the significant contribution of local and regional factors to a city’s pollution levels.

The cities with the worst pollution spikes in 2020 over 2019 include Gurugram, Lucknow, Jaipur, Visakhapatnam, Agra, Navi Mumbai, and Jodhpur. Kolkata is the only mega city in this group.

In 37 cities that are otherwise showing stable or declining seasonal averages, their peak pollution levels have risen significantly during winter. These include Aurangabad, Indore, Nashik, Jabalpur, Rupnagar, Bhopal, Dewas, Kochi, and Kozhikode. On the other hand, in north India, other cities, including Delhi, have experienced the reverse, that is, an increase in the seasonal average but decline in the seasonal peak.

During winter, cool and calm weather traps and spikes daily pollution, particularly in north Indian cities located in the Indo Gangetic Plain. This year, the average level of PM2.5 during the summer and monsoon months was considerably lower than the previous year due to the summer lockdown. However, the winter PM2.5 concentration has risen compared to the 2019 winter in many cities across regions.

“This bouncing back of pollution post-lockdown unmasks the high impacts of local and regional pollution. This demands quicker regional reforms to curb pollution from vehicles, industry, power plants and waste burning to curb the winter pollution and also sustain annual improvement at a regional scale with speed,” says Anumita Roychowdhury, CSE’s executive director in charge of research and advocacy, said in a statement.

The analysis is part of the air pollution tracker initiative of CSE. It’s based on publicly available granular real time data (15-minute averages) from the Central Pollution Control Board (CPCB). The data is captured from 248 official stations under the Continuous Ambient Air Quality Monitoring System (CAAQMS) spread across 115 cities in 22 States and Union Territories. The CSE analysts only considered cities that had readings for both years in at least 75% of the winter days (from October 1 to January 31).

When ranked from the most to the least polluted cities, 23 of the most polluted cities are from north India. While Mysuru is the least polluted, followed by Satna in Madhya Pradesh and Kochi in Kerala, Ghaziabad is the most polluted city in the northern belt. There are only four cities (Satna, Mysuru, Vijaypura and Chikkamagaluru) that have met the national 24-hour standard (60 μg/m3) during the winter season. Satna and Maihar in Madhya Pradesh, and Mysuru in Karnataka, are the cleanest cities in the country, according to the report.

The authors of the study also emphasise that rather than mega cities, it was the smaller and upcoming cities that were emerging as pollution hotspots. “ This report makes it amply clear that this winter pollution challenge is not limited to mega cities or one specific region; it is an omnipresent problem and requires urgent and deliberate action everywhere. This requires quicker reforms and action in key sectors of pollution — vehicles, industry, power plants and waste management to control winter pollution and bend the annual air pollution curve.”

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Printable version | Apr 22, 2021 3:20:49 AM | https://www.thehindu.com/sci-tech/energy-and-environment/winter-pollution-shows-rise-in-most-indian-cities-says-cse/article33926354.ece

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