A thick layer of smog covered New Delhi as air quality deteriorated across several northern Indian cities with the onset of colder weather. Residents were experiencing respiratory problems, irritated eyes and migraines, while pulmonologist Nikhil Modi said he was seeing increasingly severe complaints, including among younger people. He said lung cancer was now affecting patients around 35 who had never smoked, whereas it had previously been more common among smokers in their sixties.

Air pollution reportedly reached exceptionally high levels during Diwali despite restrictions on fireworks. Local authorities had banned older polluting cars from the city centre, partially halted construction and encouraged officials to work from home or use public transport. Field burning remained officially prohibited, but 200 fires were reported the day after Diwali. Sociologist Vasundhara Bhojvaid said pollution was less well measured and its health effects less well understood in rural areas. Some wealthier residents were temporarily leaving cities for the mountains or Europe to escape the pollution.