New analysis of winter air pollution (till January 11) in cities of Indo-Gangetic Plains (IGP) carried out by Centre for Science and Environment (CSE) showed clean air gains during lockdown and monsoons had been lost with the reopening of the economy and the hostile winter weather.

Interestingly, the analysis said that the rise in pollution had also been synchronised across the region with varying patterns.

While this was expected, the analysis of real-time data from monitoring stations outside the National Capital Region (NCR) in the larger Indo-Gangetic Plains showed newer patterns in winter pollution this year.

“Cities in central and eastern UP and Bihar (regions south of the NCR) also show high winter pollution, but levels are similar or lower compared to 2019. Combination of reopening of the economy and changing meteorology is responsible for high winter pollution, but this regional variation calls for a nuanced and robust pollution control strategy,” it said.

Higher PM 2.5 levels is a typical and predictable winter trend when continuous emissions from sources like vehicles, industry, construction, and episodic pollution from biomass burning get trapped due to weather changes.

“This year, the trend has set in almost two weeks earlier in the season. There is a clear difference in winter pollution pattern between IGP regions north and south of the NCR. Even though the average level of PM 2.5 for the summer and monsoons in 2020, is considerably lower than previous year due to lockdown, the levels this winter have risen beyond the 2019 levels in almost all monitored cities in Punjab and Haryana (regions north of the NCR),” it said

Analysis was done of data recorded by six air quality monitoring stations in Patna, five in Lucknow, two in Gaya and Muzaffarpur each and one station each in the rest of cities under Continuous Ambient Air Quality Monitoring System (CAAQMS) of the CPCB.

Weather data for Amritsar, Ambala, Chandigarh, Lucknow and Patna have been sourced from the weather stations of Indian Meteorological Department (IMD) located at airports in each city.

The report found that the annual average level of PM2.5 is not lower in many cities this year despite lockdown, while several bigger cities witnessed a reduction and many smaller towns and cities experienced an increase.

In UP the worst performer was Agra with an increase of 9 per cent as compared to last year followed by Moradabad 5.5 per cent, while Varanasi showed improvement of 31 per cent.