As smoky and hazy skies are back to haunt Delhi-NCR after a few months of blue skies and clean air, experts have cautioned people to brace for the winter season saying higher pollution level may worsen the impact of COVID-19.

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Environment and health experts have asked people, especially those vulnerable to COVID-19 attack, to be more careful as the chronic exposure to air pollutants is associated with severe infections and higher mortality. They feel that lungs compromised due to pollution could lead to complications like pneumonia during COVID-19. "There is abundant evidence that exposure to air pollution increases our vulnerability to respiratory viral infections both in terms of transmission and the severity of the infection, said the climate campaigner, Greenpeace India.

"Researchers have linked air pollution with mechanisms that may reduce our immune defenses such as damage to human airways, cilia and epithelial barriers. In the case of COVID-19, current evidence indicates that chronic exposure to air pollutants is associated with more severe infections and higher mortality," he said.

Every year the winter season brings with it cold, polluted air in northern India and the problem this year can worsen due to the pandemic. A layer of smoky haze lingered over Delhi-NCR on October 15 with the air quality in the region hitting 'very poor' levels, even as stricter anti-air pollution measures, including a ban on electricity generators, came into force under the Graded Response Action Plan (GRAP). According to Health Ministry data updated on October 16, India's COVID-19 caseload rose to 73,70,468 with 63,371 new infections being reported in a day.

Doctor Shuchin Bajaj from Ujala Cygnus Group of Hospitals in Delhi, said at the onset of winter and stubble burning, cases of Asthma and COPD (chronic obstructive pulmonary disease) rise but one needs to be more careful this year because of the pandemic. "When your lungs are compromised and weak, you have more chances of developing complications like pneumonia during COVID. You have to take care of SMS - social distancing, mask and sanitisation more so in the coming days," Bajaj said. According to SAFAR (System of Air Quality and Weather Forecasting and Research), contribution of farm fires to Delhi's PM2.5 concentration was around 6 percent on October 15. It was only around one percent on October 14 and around 3 percent on October 13, October 12 and October 11.

NASA's satellite imagery showed a large cluster of farm fires near Amritsar, Patiala, Tarn Taran, and Firozpur in Punjab, and Ambala and Rajpura in Haryana. The Central Pollution Control Board (CPCB) swung into action on October 15 by sending its 50 teams to inspect pollution hotspots in Delhi and neighbouring cities and file reports from field for next two months. The Environment Ministry recently held a meeting with the CPCB and officials of Delhi, Haryana, Punjab, Rajasthan and Uttar Pradesh on stubble burning.

Ravindra Khaiwal, Associate Professor, Environmental Health, PGI Chandigarh, said that air pollution has been identified as a major risk factor for premature deaths. "Air pollution has been identified as a major risk factor for premature death and non-communicable diseases. There are emerging evidence that air pollution could be linked with the severity of COVID-19 conditions," he said, adding that stubble burning could spike pollution by 20-40 percent.

Experts advise that wearing mask is the most effective way to protect oneself from pollution as well as COVID-19. "Wearing face mask is single most effective way of keeping oneself safe from COVID-19 as well as pollution this winter. Avoiding strenuous outdoor exercise during peak pollution hours is also beneficial. For people with chronic lung diseases, it is very important to be compliant to their treatment," Arunesh Kumar, Head Respiratory Medicine/Pulmonology at Paras Hospital, said.

Piyush Goel, a doctor from Columbia Asia Hospital, Gurgaon, said while people need to follow basic principles of wearing masks, sanitising hands and maintaining distance, the government should ensure policy measures to prevent pollution. "Wear face mask covering nose and mouth upto chin, maintain social distancing and ensure hand hygiene. Face mask will also help to prevent impact of pollution such as particulate matters. "The government should ensure policy measures to prevent pollution. No stubble burning should be allowed, vehicular pollution should be avoided, and construction protocols should be followed. Besides, we must recognise that it is a collective responsibility of people to work together to defeat both COVID-19 and pollution," Goel said.

Khaiwal said the problem of pollution needs public policy and industry partnerships. "The government had last year launched the National Clean Air Program (NCAP) to reduce air pollution by 20-30 percent by 2024. Public participation is vital as we are aware of the pollution problem. Still, our contribution is minimal, which we do by taking simple steps like recycling and segregating household waste, use of energy-efficient electronics and e-vehicles. "There should be policies to incentivise the public for walking and cycling. Cities should also adopt and promote a non-motorized mode of transportation. Industries should be encouraged to adopt a healthy business model having a focus on pollution reduction," he said. India's coronavirus death toll climbed to 1,12,161 with 895 fatalities reported on October 16.