Delhi gets off to its most polluted October start in three years

Delhi’s annual battle with air pollution appears to have started on a worrying note, with the Capital recording an average Air Quality Index (AQI) of 171 during the first week of October 2026, its most polluted opening week in three years. The early deterioration has raised concerns about the coming weeks, when falling temperatures, stagnant air and seasonal emissions often combine to worsen pollution.

Although the average AQI falls in the ‘moderate’ category under India’s national air-quality scale, the trend highlights the challenges facing the Capital as it enters the winter pollution season. Low wind speeds, vehicular emissions, construction dust and the seasonal burning of agricultural residue in neighbouring states are among the factors that could influence air quality in the weeks ahead.

Amit, 26, an air quality researcher from IIT Delhi, said, “The early rise in pollution is a reminder that Delhi needs to address emissions before the winter season reaches its peak. Waiting until air quality deteriorates further can make the situation more difficult to manage.

Weather conditions The transition from the monsoon to winter is a critical period for Delhi’s air quality. During the monsoon, rainfall helps remove some airborne pollutants, while stronger winds can carry them away. As the rains withdraw, these effects diminish, allowing pollutants to accumulate.