The assumption is that industrial activities are high contributors to air pollution, but recent studies held during the lockdown suggest human activities including transportation may have a far higher impact on air quality. Here we talk about emissions in industrial and metro cities, their impact, and where these findings take us.
Bengaluru, 22/12/21 - The COVID-19 lockdown over the past months has revealed the extent of human impact on the environment.
Human activities such as transportation, industrial activity, urbanization etc. have an adverse impact on climate change, and in particular on-air quality. One of the most common pollutants, particulate matter or PM (PM2.5 and PM10), is also among the most dangerous. To study the distribution of PM over the periods of lockdown and before, 8 representative cities (metros and industrial cities) along the Indo-Gangetic Plain have been analyzed.
Air pollution levels in Indian metro cities as opposed to industrial cities were analyzed. Contrary to assumptions, the impact of air pollution on metro cities is far greater than its impact on industrial cities in india. Recent data from CPCB CAAQMS monitors at metro and Tier II cities shows that average levels of PM2.5 and PM10 during festival periods surpass the pollution levels from industrial cities. Since India has a highly vaccinated population against the COVID-19 virus, there was much increase in vehicular movement and other activities during the festive season. This increased pollution levels in metro and tier-II cities.
Methodology - Air quality data for Indian cities including Mumbai, Kolkata, Ahmedabad, Chandigarh, and Jaipur was sourced from the Central Pollution Control Board (CPCB).
Cities |
State |
Location |
Type |
Kurukshetra |
Haryana |
UGP |
Metro Tier II |
Yamuna Nagar |
Haryana |
UGP |
Industrial |
Chandigarh |
Haryana/Punjab |
UGP |
Metro Tier II |
Asansol |
West Bengal |
LGP |
Industrial |
Kolkata |
West Bengal |
LGP |
Metro Tier I |
Ahmedabad |
Gujarat |
UGP |
Metro Tier I |
Ankleshwar |
Gujarat |
UGP |
Industrial |
Jaipur |
Rajasthan |
Northwest Arid |
Industrial/Metro Tier II |
Tier |
I and II |
Geography |
Along Indo-Gangetic Plain |
Type |
Metros and Industrial Cities |
2020 (Lockdown 1) |
Pre lockdown period |
Feb 24 - Mar 24 |
Lockdown period |
Mar 25 - May 3 |
|
2021 (Lockdown 2) |
Pre lockdown period |
Mar 28 - April 28 |
Lockdown period |
April 29 - May 29 |
Note: In 2020, the country saw a complete lockdown of all cities and industries, except those operating essential services. This period witnessed massive reductions in air pollution levels. However, in 2021, cities saw almost a complete lockdown, whereas industries were mostly running albeit with limited production.
A pictorial representation of particulate matter pollutants - PM2.5 and PM10
Kolkata is a metro while Asansol is an industrial city. Their respective sources of emissions are different, and so are the reductions in pollution levels.
Observation: In this case, pollution reduction was greater in the metro than the industrial city.
PM10 comparison between Kolkata and Asansol before and during the lockdown in 2020 and 2021
PM2.5 comparison between Kolkata and Asansol before and during the lockdown in 2020 and 2021
The MIDC Industrial area, located in Mahape (Navi Mumbai), has industries ranging from paper mills to heavy machinery.
Observation: It is possible that industrial emissions are an equal contributor of air pollution in Mumbai, as vehicular emissions
PM10 comparison between Mumbai metro and Mumbai Mahape before and during the lockdown in 2020 and 2021
PM2.5 comparison between Mumbai metro and Mumbai Mahape before and during the lockdown in 2020 and 2021
In this belt, Chandigarh is a Tier II metro city, Yamunanagar is industrial, and Kurukshetra is a mix of the two.
Observation: The metro region recorded a higher reduction than the industrial area.
PM2.5 comparison between Chandigarh, Kurukshetra and Yamunanagar before and during the lockdown in 2020 and 2021
PM10 comparison between Chandigarh, Kurukshetra and Yamunanagar before and during the lockdown in 2020 and 2021.
Ahmedabad is a metro and Ankleshwar is an industrial city.
PM2.5 comparison between Ahmedabad and Ankleshwar before and during the lockdown in 2020 and 2021
PM10 comparison between Ahmedabad and Ankleshwar before and during the lockdown in 2020 and 2021
Jaipur has a mix of residential and industrial areas.
Observation: This indicates that the restrictions were not implemented completely, and there was no slowing down of economic activity.
Tier 1 cities saw a higher reduction in pollution than Tier 2 cities. This could be because Tier 1 cities may have had a complete and enforced lockdown, and therefore a vaster reduction in economic activity.
The reduction of particulate matter is higher in the metro cities that are primarily residential, than in cities that are primarily industrial.
Industries were probably still operating at reduced capacity through the lockdown, but importantly, the movement of people and goods is a significant contributor to particulate matter. There is tremendous improvement to air quality when economic activity is cut down.
Comparison of PM10 levels in Jan 2020 and Jan 2021
Comparison of PM2.5 levels in Jan 2020 and Jan 2021
Evidently, the respite in air pollution over the lockdown has not made enough of an impact on policy. Policymakers need to offer an alternate solution for a livelihood by working with changemakers and advocacy groups to offer sustainable alternatives.
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