Over Last Decade, Several Major Indian Cities Did Not Have Good Air Quality
The Wire Staff
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Bengaluru: Between 2015 and November 2025, not a single Indian city among a list of 11 major ones had good air quality, according to an analysis of the Central Pollution Control Board (CPCB)'s pollution data by research and communication initiative Climate Trends.
Delhi retained the top spot as the city with the most polluted air over the decade, according to the analysis.
As on Thursday (November 27), the air quality index or AQI in the national capital was 377, in the “very poor” category, according to the Indian Institute of Tropical Meteorology’s air quality and weather bulletin for the city on November 28.
India's AQI system
India’s National Ambient Air Quality Standards have set limits on the permissible levels of pollutants in the air.
The concentration of PM10 (particulate matter that is less than ten microns in diameter) in ambient air should not be more than 100 µg/m3 (micrograms per cubic metre) across a 24-hour period, and 60 µg/m3 annually.
For fine particulate matter or PM2.5 (particulate matter that is less than 2.5 microns in diameter), it should not be more than 60 µg/m3 for a 24-hour period, and 40 µg/m3 annually.
Similarly there are limits for sulphur dioxide, nitrogen dioxide and other pollutants.
India’s AQI is a measure of the levels of at least three such air pollutants in the air. One of them has to be particulate matter (both PM2.5 and PM10).
AQI categories range from 0 to 500. While an AQI between 0 to 50 is considered “good”, an AQI between 401-500 is categorised as “severe”, and is the worst air quality level per standards followed by the CPCB. The higher the AQI, the higher the impacts of polluted air on people.
India’s current system of measurement caps the AQI at 500 – which means that even if AQI crosses 500, this is not recorded.
The permissible levels of pollutants in India are higher than the safe levels prescribed by the World Health Organisation (WHO). For instance, the WHO recommends that levels of PM2.5 should be no more than 15 µg/m3 for a 24-hour period (and 5 µg/m3 annually). Similarly, PM10 levels should not be more than 50 µg/m3 for a 24-hour period (and 20 µg/m3 annually).
Ten-year trends
Climate Trends, a research and communication initiative, analysed the open-access data on pollution levels across 11 major Indian cities provided by the CPCB. It found that from 2015 to November 2025, none of these cities were safe in terms of air quality. The AQIs of all assessed cities consistently fell within ranges that indicate moderate to hazardous pollution levels, with some cities routinely breaching recommended safe limits.
Delhi remained the most polluted city throughout the study period: its AQI levels were above 250 (in 2016) and around 180 in 2025. Though there were minor year-to-year fluctuations, the city never approached safe thresholds, the report said.
Lucknow, Varanasi, Ahmedabad and Pune also show prolonged periods of elevated AQI.
Per the report, Lucknow and Varanasi started with extremely high levels (often above 200), and although both cities showed improvement after 2019, their 2025 AQI values still remain above healthy limits. Ahmedabad also showed a similar pattern, with AQI reductions after 2017 but still around 100-120 for most years.
Kolkata, Chennai, Chandigarh, Visakhapatnam and Mumbai had moderate AQI values compared to northern cities but were still not within safe levels, though some of these cities (like Chennai and Mumbai) showed improvement after 2020.
Bengaluru had the lowest AQI values (between 65 and 90). But these too is higher than safe limits.
Technology can help address many local pollution sources within a specific airshed, but this requires reliable data, said S.N. Tripathi, who is dean at IIT Kanpur's Kotak School of Sustainability, in a statement.
“There are numerous ways to be proactive, but we need an intelligent decision-support system to guide those choices – whether it's assessing if an anti-smog gun is effective, cost-efficient or even necessary. Poorly designed interventions can end up causing more pollution than they prevent.
“With data, we can evaluate the impact of any measure in real time. Cities are increasingly using data-driven approaches for planning, and technology now provides the insights needed to make smart short, medium and long-term decisions,” he said.
Delhi AQI in ‘very poor’ category
As on November 27, the AQI in the national capital was 377, in the “very poor” category.
The government’s Sameer mobile application, which shows AQI levels across the country, showed that some stations in Delhi (R.K. Puram and Nehru Nagar) had recorded an AQI of 400 and above – putting these areas in the “severe” category.
A screenshot from the Sameer app on Friday, November 28.
Though the government implemented the National Clean Air Programme (NCAP) in 2019 to improve air quality in India by reducing particulate matter concentrations by 20-30% by 2024 across a list of around 130 cities, the programme – which has used up public funds amounting to nearly Rs 7,600 crore – has not yielded the expected results.
In fact, a submission by the Union environment ministry to parliament in July this year stated that pollution levels in 25 Indian cities listed under the NCAP have witnessed a spike instead of a decline.
This article went live on November twenty-eighth, two thousand twenty five, at thirty-three minutes past ten at night.The Wire is now on WhatsApp. Follow our channel for sharp analysis and opinions on the latest developments.