Delhi posts best Jan-Sep air quality since 2018, AQI averages 164 this year

The environment ministry said Delhi's average AQI dropped to 164 in Jan-Sep 2025, with no 'severe' days recorded, while PM2.5 and PM10 levels fell to their lowest since 2018, excluding 2020

The Ministry of Environment, Forest and Climate Change on Wednesday reported an improvement in Delhi’s air quality for the period from January to September 2025. The average Air Quality Index (AQI) for the city during this period was recorded at 164, compared with 178 in 2024 and 167 in 2023.

 

For the monsoon months of July to September, the city recorded an average AQI of 91, matching 2024 levels and marking one of the lowest readings over the past eight years, excluding 2020 when Covid-related lockdowns were in place, the ministry said.

 

It further added that the January-September period in 2025 did not see any day with AQI exceeding 400, which falls under the ‘Severe’ or ‘Severe+’ categories. In comparison, similar periods in previous years recorded several such days: 3 in 2024 and 2023, 1 in 2022, 6 in 2021, 2 in 2020, 7 in 2019, and 6 in 2018. The period also saw 75 ‘Satisfactory’ (51-100 AQI) air quality days, the highest since 2018, except for 2020. 

 

Concentrations of particulate matter were also lower. Average PM2.5 levels stood at 69 micrograms per cubic metre (µg/m³), compared with 81 µg/m³ in 2024. PM2.5 refers to fine particulate matter measuring 2.5 micrometres or smaller in diameter. These tiny particles, comprising dust, soot, smoke, and liquid droplets, can penetrate deep into the lungs and bloodstream, causing respiratory and cardiovascular diseases, lung cancer, and asthma.

 

While the national capital witnessed relatively lower PM2.5 levels, according to the World Health Organization (WHO), annual PM2.5 levels above the recommended limit of 5 µg/m³ are linked to around 1.5 million deaths in India each year.

 

Meanwhile, PM10 levels averaged 161 µg/m³, down from 181 µg/m³ the previous year. These figures represent the lowest readings for the corresponding period since 2018, excluding 2020.