Winter Pollution Worsening In Madhya Pradesh And Chhattisgarh, Says CSE Study

It is not only the northern part of India that is in the grip of severe winter pollution. Several cities in other regions — including the central Indian states of Madhya Pradesh and Chhattisgarh — are experiencing a worsening of winter pollution, finds a latest analysis from Centre for Science and Environment (CSE).

"Even though real time air quality data is extremely limited in this region, whatever real time data is emerging from only 17 cities of these two big states indicates a growing crisis and vulnerability to winter smog. This demands early and stronger multi-sector action at a regional scale to meet the clean air targets,” says Anumita Roychowdhury, executive director, research and advocacy, CSE.

"Gaps in air quality data and lack of quality control of data make it difficult to construct reliable air quality trends and do proper risk assessment,” says Avikal Somvanshi, programme manager, urban lab, CSE.

“The worsening of air quality in the region has not drawn adequate public attention. In winter, air quality of cities like Singrauli, Gwalior, Jabalpur and Katni could get nearly three times worse than their annual average levels.”

CSE has analysed air quality status in cities of Madhya Pradesh and Chhattisgarh. This is a continuation of the air quality tracker initiative of the Urban Data Analytics Lab of CSE that was started last winter.

The objective of this new analysis has been to understand the trends and magnitude of winter pollution in major cities of different regions that have real time air quality monitoring systems.

This is an assessment of annual and seasonal trends in PM2.5 concentration for the period 1 January 2019 to 12 December 2021. This analysis is based on real time data available from the current working air quality monitoring stations in central India. A huge volume of data points have been cleaned and data gaps have been addressed based on the USEPA (United States Environmental Protection Agency) method for this analysis.

The analysis covers 18 continuous ambient air quality monitoring stations (CAAQMS) spread across 17 cities in the two states: two stations in Gwalior and one station each in Bhopal, Damoh, Dewas, Indore, Jabalpur, Katni, Maihar, Mandideep, Pithampur, Ratlam, Sagar, Satna, Singrauli, Ujjain, Bhilai and Bilaspur.

Air quality monitoring is still very limited in the central region. Cities in MP have data available for over two years; but real time monitors in Chhattisgarh became operational only in the latter half of 2021, which limits the possibility of assessing long term trends. Therefore, the data is indicative of the current status of air quality and seasonal variations in particulate pollution in medium and smaller cities in the region.

The analysis shows that air pollution during winter is a problem in all cities in these two states, with Gwalior and Singrauli having the worst air quality — as bad as the winter air quality of cities in the National Capital Region and Uttar Pradesh.

Nitrogen dioxide (NO2) pollution is also high in these cities, with Indore recording the highest for the region. The limited air quality data in the region indicates that it has not changed much from the 2020 levels. But due to limited historical data, it is difficult to comment on the regional air quality trends.

Major cities like Bhopal (38 days), Indore (36 days), Gwalior (72 days), Jabalpur (49 days) and Ujjain (30 days) have recorded over a month of poor or worse air quality in 2021 so far. These bad air quality days are concentrated during winter months. Cities in the east abutting the Indo-Gangetic Plains are dirtier compared to the rest of the cities in the region.

Traffic is a major contributor to pollution: All cities show peaking of hourly NO2 concentrations between 6 pm and 8 pm which coincides with the evening rush hour. Hourly NO2 levels in Gwalior increases five-fold between noon and 6 pm.

The cycle is equally sharp in other cities, with 2.5-4.3 times increases in the evening (from afternoon). All cities also have a morning NO2 peak around 7-8 am, but this is relatively smaller than the evening peak. In Indore, high NO2 levels persist till midnight indicating pollution generated by night-time truck movement in the city.

Diwali was a mega polluting event: The pollution level on Diwali night (8 pm to 8 am) in cities in this region shot up by 1.4-3.9 times the average level recorded on seven nights preceding Diwali.

Bhopal had the greatest pollution build-up on Diwali night, with a 3.9-fold increase in night-time PM2.5, followed by Ujjain that saw a 3.7 fold increase. Sagar, Bilaspur and Damoh registered very low PM2.5 levels with no impact of Diwali.

“The central Indian region — that includes critically polluted industrial areas — requires urgent attention under the National Clean Air Programme. While strengthening the air quality monitoring network for proper risk assessment, action should be tightened in critically polluted areas and implementation of a multi-sector clean air action plan scaled up to meet time-bound clean air targets," said Roychowdhury.