Delhi Air Quality Worsens as Winter Approaches

Delhi Air Quality Worsens as Winter Approaches

October is bringing cooler mornings to Delhi, and concerns about air quality are returning. With the monsoon over and winter ahead, the capital is entering a season that has often left it among the world’s most polluted cities.

Recent Rise in AQI Levels

Delhi’s Air Quality Index rose quickly over the weekend. It moved from 90 on Friday to 159 on Saturday and 187 on Sunday, according to Central Pollution Control Board data. The citywide reading stayed in the moderate category on Sunday. However, dry weather and slower winds are allowing pollutants to build up ahead of winter.

Temperatures have also fallen across Delhi and the National Capital Region after the monsoon withdrew. The minimum temperature in Delhi stood at 17.1 degrees Celsius on Sunday, which was 1.3 degrees below the seasonal average, the India Meteorological Department said.

Elevated Readings at Several Stations

With no rainfall expected over the coming week, pollutant levels may continue to pressure the city’s air quality. Several monitoring stations have already recorded high pollution. ITO reported an AQI of 430 on Sunday, placing it in the severe category.

On Saturday, Anand Vihar recorded an AQI of 348, while Mundka registered 227 and Jahangirpuri reported 212. Chandni Chowk stood at 188, and both Vivek Vihar and Rohini registered 187. Punjabi Bagh reported 171, followed by Narela at 165, CRRI Mathura Road at 158, and Dwarka Sector 8 at 155. On Sunday, 22 monitoring stations across Delhi recorded poor air quality, showing that pollution was spreading to several parts of the city.

October Trend and Contributing Factors

The deterioration has been visible through October. On October 1, the AQI at ITO stood at 132 at 5 pm, while Jahangirpuri recorded 216 and Punjabi Bagh registered 178. Anand Vihar, which often ranks among the city’s more polluted locations, had an AQI of 96 at the same time.

The recent rise follows Friday’s relatively clean reading of 90. The Central Pollution Control Board classifies AQI readings of 101–200 as moderate, 201–300 as poor, 301–400 as very poor, and 401–500 as severe.

Dry weather, lower wind speeds, and emissions from vehicles, road dust, and construction activity are among the immediate factors behind the worsening air quality. Rain helps wash pollutants from the atmosphere, while stronger winds disperse them. As these conditions become less frequent after the monsoon, pollution from everyday activities can stay concentrated closer to the ground.

Seasonal changes can further worsen the situation. As temperatures fall toward winter, lower mixing heights and stagnant winds limit the vertical and horizontal dispersion of pollutants. This allows pollution levels to rise even without a major increase in emissions.

Government Response and Year-to-Date Data

Despite the recent deterioration, Delhi Environment Minister Manjinder Singh Sirsa said on Saturday that the capital had recorded 211 days of good, satisfactory, and moderate air quality so far this year. He described this as the city’s best performance since 2016, excluding the Covid-affected year 2020.

With more than two months remaining in 2026, the number of days with good-to-moderate air quality has already exceeded the full-year totals recorded in several previous years. These included 200 days in 2025, 209 in 2024, 206 in 2023, 159 in 2018, and 110 in 2016. Sirsa also said the number of days with poor, very poor, and severe air quality had declined to 79 during the corresponding period this year, compared with 168 in 2016.

The latest rise in AQI highlights the seasonal challenge facing Delhi as winter approaches. With dry conditions expected to continue, the coming days will be crucial in determining whether pollution levels keep climbing.