Winter smog threatens to worsen Covid-19 crisis across South Asia

As autumn settled over South Asia in October 2020, the region faced a collision of two crises. The pandemic that had already claimed thousands of lives was about to meet the annual smog season—a toxic convergence that public health experts feared could overwhelm already fragile health systems across the subcontinent.

Months earlier, when lockdowns first shuttered factories and emptied roads, the air had cleared dramatically. Cities from Peshawar to Guwahati experienced weeks of unprecedented clarity, a glimpse of what cleaner skies might look like. But as restrictions eased, the pollution crept back. Now, with winter approaching, the familiar toxic soup was returning—agricultural waste burning, industrial emissions, vehicle exhaust, and brick kilns combining into a seasonal haze that would blanket millions of people. Bangladesh, India, Nepal, and Pakistan had become home to the world's most polluted cities, surpassing even China. The toll was staggering: millions died annually from breathing poisoned air, with life expectancy cut by five years on average across the region, and by more than eight years in the worst-affected areas of northern India.

What made this moment particularly dangerous was emerging scientific evidence linking the two threats. Researchers at Harvard University had examined Covid-19 death rates against historical pollution levels across the United States and found that high concentrations of PM2.5—the finest particulate matter—in the years before the pandemic were associated with an 8 percent increase in coronavirus fatalities. A study from the Netherlands suggested the risk could be even steeper, with small increases in pollution exposure raising death rates by up to 21 percent. The mechanism was becoming clearer: pollution damaged lung function over time, leaving people more vulnerable when the virus arrived. The particles themselves could carry the virus farther through the air and potentially allow it to survive longer in the atmosphere.

In India, which had recorded the world's second-largest caseload and was adding roughly 70,000 cases daily by early October, officials acknowledged the danger. TK Joshi, a health expert at India's Central Pollution Control Board and member of the prime minister's Covid-19 task force, warned that winter air pollution could compound the pandemic crisis at a moment when health infrastructure was already under severe stress. "The quality of air has a bearing on a person's immunity," he said. Poornima Prabhakaran, an epidemiologist at the Public Health Foundation of India, framed it starkly: vulnerable populations—the elderly, pregnant women, those with existing health conditions—would face a "double whammy" of poor air quality and viral exposure. People with compromised lung function from years of pollution exposure would be more susceptible to severe illness.

Yet across South Asia, governments had largely failed to act. India's National Clean Air Programme was dismissed by activists as insufficient. Bangladesh, Pakistan, and Nepal lacked even basic equipment to monitor air pollution systematically, let alone strategies to address its sources. In early October, Delhi's air quality slipped into the "poor" category for the first time in three months as farmers upwind burned rice and wheat stubble to clear fields for winter crops—a practice that typically accounts for around 20 percent of the capital's PM2.5 during peak burning season. The government responded with diesel generator bans and water cannons, measures that addressed symptoms rather than causes. Across the Indo-Gangetic plains, pollution was equally severe, yet most people remained unaware of the risks because monitoring networks simply did not exist.

Rural women faced particular peril. In villages across the region, millions still cooked with biomass—fuelwood and animal dung burned in traditional stoves that filled homes with toxic soot. Recent World Bank research had found a positive correlation between household air pollution exposure and Covid-19 fatality rates. As the pandemic spread into rural areas, women and children who spent long hours indoors would face compounded respiratory risk. Health systems already strained by the pandemic would face surging cases of acute respiratory illness with the onset of winter.

Pakistan, which had not yet been hit as hard as India, braced for a potential second wave. The virus's reproduction rate had climbed above one in cities like Lahore and Faisalabad, and reached a staggering four in Quetta. The country faced the same air pollution crisis as northern India, with nearly 22 percent of premature deaths attributed to pollution and annual costs of roughly 2.5 percent of GDP. Yet many Pakistani cities did not even collect or report air quality data. Environmental lawyer Ahmad Rafay Alam warned that the smog season would make Covid-19 symptoms "much, much more severe," calling for immediate shifts to renewable energy, crackdowns on polluting industries, and at minimum, mass distribution of masks.

In Nepal, Kathmandu—one of the world's most polluted cities—had briefly cleared during lockdown, only to become a dust bowl again as traffic and industry resumed. The bowl-shaped valley trapped pollutants through winter, and experts worried the combination of outdoor air pollution, indoor cooking fumes, and poor ventilation would create ideal conditions for severe respiratory illness. Yet the Nepali government had not begun joint research linking air pollution and Covid-19. Across the entire region, the absence of adequate testing for the virus and adequate monitoring of air quality meant that the true scale of the converging crisis remained unknown—a dangerous blind spot as winter approached.