A significant drop in Air Pollution levels across India after about a month COVID-19 lockdown.  

Author :  K K Aggarwal and Dr Anil Kumar, President and Director HCFI 

The levels of NO2 and Ozone across India are within the National Ambient Air Quality Standards.

 No clear relationship observed between current Air quality vs Confirmed COVID-19 cases in India.

India

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New Delhi, April 26, 2020 :

During COVID-19 pandemic and lockdown enforced, countries across world have reported a significant drop in air pollution and witnessed improvement in air quality.

In India, the most significant improvement in air quality during lockdown was observed in cities across Indo-Gangetic plain as in most of the normal days, particularly in winter months, particulate matter (PM10 and PM2.5 levels) and NO2 values are high in Indo-Gangetic plain due to geographical location and other factors including very high population density and spread of industrial clusters.

As per an earlier analysis done by Team of HCFI, after 11 days COVID-19 lockdown, the level of  particulate pollution (particulate matter,  PM10 and PM2.5) dropped by nearly 60% in  Delhi.  PM10 (particulate matter 10 micrometres or less in diameter) and PM2.5 (particulate matter 2.5 micrometres or less in diameter) are particles present in the air that are classified as pollutants and can harm human health.  The deadliest particle in Delhi’s foul air is PM 2.5 (primarily come from combustion – fires, automobiles and power plants), which increases the likelihood of respiratory and cardiovascular diseases.

Across the Globe, studies have been conducted to get a clear relationship between air pollution exposure and COVID-19 confirmed cases as high levels of air pollution can cause damage to the lungs and thus makes one, more susceptible to either getting the infection or to getting complications from  COVID-19. The World Economic Forum also said that people living with poor air quality may be more susceptible to COVID-19 disease.

A recent study w.r.t. Exposure to air pollution and COVID-19 mortality in the United States  by Xiao Wu et.al of  Dept. of Biostatistics, Harvard T.H. Chan School of Public Health, USA, indicates that Coronavirus patients in areas that had high levels of air pollution before the pandemic, are more likely to die from the infection than patients in cleaner parts of the country. This study offers the first clear link between long-term exposure to pollution & Covid-19 death rates.

The authors in above study found that an increase of only 1 μg/m3 in PM2.5 is associated with a 15% increase in the COVID-19 death rate. Results are statistically significant and robust to secondary and sensitivity analyses. They have concluded that a small increase in long-term exposure to PM2.5 leads to a large increase in COVID-19 death rate. The study results underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis.

In this regard, Team of Experts of HCFI have done detailed analysis of air quality data ( Air Quality Index- AQI, PM10, PM2.5, NO2 and Ozone) from about 180 Continuous Ambient Air Quality Monitoring Stations (CAAQMS) across India and correlated with Confirmed COVID-19 cases . Status of Confirmed COVID-19 cases of various States/UTs as on 21-04-2020 and corresponding State/UT wise Air Quality status ( as per average CPCB/SPCB data w.r.t. National Air Quality Index as on 21-04-2020 at 4:00 PM) is given below in the Table

The above data of current Air Quality vs Confirmed COVID-19 cases in India do not show any clear relationship. However, long term exposure of higher levels of air pollutants, particularly higher PM2.5 levels, may weakens the immunity and thus raises the risk of COVID-19 infection. Detailed study in this regard is needed.

However, as per present study, the levels of NO2 and Ozone throughout  the India are found within the National Ambient Air Quality Standards, notified as per the Central Pollution Control Board Notification in the Gazette of India,  dated 18th November, 2009 ( PM10 std. 24 hourly = 100 microgram per meter cube, PM2.5 std. 24 hourly = 60 microgram per meter cube, NO2 std. 24 hourly = 80 microgram per meter cube and Ozone std. 1 hourly = 180 microgram per meter cube).

Though, levels of PM10 and PM2.5 have significantly declined during Lockdown period as compared to Normal days. However, levels of PM10 and PM2.5 in some States/ UTs at few locations are found above the Standards.

Though, presently, we have observed clean air due to the lockdown in India but this respite is for short term period.  After the restrictions are lifted and human activities start, there will be a sudden rise in air pollution.   But, the lockdown  during  COVID-19 has shown ways to tackle air pollution issues, only what’s needed is political will, societal interventions and strict enforcement.

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