Pollution increases Covid-19 risk: Study

Of the cities studied, Mumbai and Pune recorded the third and fourth highest ‘bad air quality days’. Representation pic

Citizens living in pollution-hit metro cities like Mumbai and Pune are at a greater risk of contracting Covid-19 than residents of other areas, a study has found. Published in peer-reviewed Elsevier Journal, the study by Indian scientists has established a link between fine particulate matter (PM2.5) and Coronavirus outbreak across India.

Covid-19 and air pollution have a double impact on people's lungs, says a co-author

"We found a significant correlation between the district level air pollution data and Covid-19 cases," said lead author Dr Saroj Kumar Sahu. In our study, we saw regions with huge amounts of fossil fuel such as petrol, diesel, and coal combustion in transport and industrial activities experiencing a lot more Covid-19 cases," said Dr Saroj Kumar Sahu, lead author of the study.

The study was carried out by scientists from Utkal University, Bhubaneswar, IITM-Pune, NIT-Rourkela, and IIT-Bhubaneswar.

Dr Sahu said health effects of air pollution and Covid-19 also had similar linkages. "PM2.5 are small sized particles affecting the upper respiratory system, and Covid-19, too, has shown similar health impacts."

The study considered cases between March and November 2020, while national PM 2.5 emissions load were estimated from base year 2019. Maharashtra recorded the second-highest emission load - 828.3 gigagram per year (Gg/Yr) of PM2.5, after Uttar Pradesh. Till November 5 last year, Dr Sahu said, Maharashtra had recorded 17.19 lakh cases, the highest in the country.

Of the 16 cities captured in the study, Mumbai and Pune recorded the third and fourth highest ‘bad air quality days' respectively. In the given period, Mumbai recorded 2.64 lakh cases and 10,445 deaths, the highest in the country, while Pune saw 3.38 lakh Covid-19 cases and 7,060 fatalities.

"What is worrying is that there is evidence that the Coronavirus sticks to fine particles like PM2.5 allowing them to move from one part to another by making the airborne transmission more effective.

Through our analysis, it has become clear that rising pollution load is becoming more of a catalyst to aggravate Covid-19 cases," said Dr Sahu. He said polluted hotspots are also triggering long-term effects and more studies are needed to understand this.

Dr Gufran Beig, Senior Scientist & Founder Project Director, System of Air Quality Weather Forecasting and Research (SAFAR) and co-author of the paper said that at hotspots within Maharashtra, exposure to air pollution can weaken lungs. "When human-induced emissions are combined with the impact of Covid-19, the damage to lungs will be much faster and worsen health conditions," he said. The study also presented two other hotspots - Nagpur and Chandrapur - that witnessed high pollution as well as higher Covid-19 cases and casualties.

Doctors' take

"The virus may be airborne but can't correlate it with pollution. In fact in the lockdown, the pollution levels had dipped but cases were on the rise. There are other variables like congestion which can't be ruled out. Also, Delhi's poor air quality in winters is a known thing. Covid-19 cases were more post winter," said Dr Rajesh Sharma, Pulmonologist, Saifee Hospital.

Dr Lancelot Pinto, pulmonary medicine specialist, PD Hinduja Hospital, said, densely populated areas with too many vehicles can lead to more fine particulate matter.

"Whether the number of Covid-19 cases reflect this population density and movement, both risk factors for Covid-19, or whether there is a causal link between the exposure to such fine particulate matter and the disease is difficult to prove. However, even if the fine particulate matter is a surrogate for overcrowding and movement, the message that we need to improve air quality cannot be emphasised enough."

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No. of big cities that were studied by the researchers