Top 20 polluted stations of 2024 located in Delhi-NCR: Study assesses air quality after NCAP launch

According to the Health Effects Institute (HEI) analysis, titled ‘Assessment of Changes in Air Quality in Indian Cities Since the Launch of the National Clean Air Programme’, Delhi-NCR accounts for nearly all of the most polluted monitoring stations in 2024. Jahangirpuri in North Delhi emerged as the most polluted station in the country, recording an annual average PM10 concentration of 276.1 µg/m³.

Trend analysis for the Capital shows a mixed but largely improving picture when long-term data is examined. (see box)

Using raw PM10 data, 21 of the 27 stations in the Capital showed declining trends, with reductions ranging from 0.3 to 9.7 µg/m³ per year even as most were not statistically significant. In contrast, Punjabi Bagh and R.K. Puram recorded notable increases in PM10 levels. When the data were deseasonalised, the number of statistically significant trends increased: 19 stations showed declining PM10 trends, with the steepest reduction observed at Jawaharlal Nehru Stadium (around 7.5 µg/m³ per year).

With regards to PM2.5 levels, 22 stations showed declining trends after deseasonalisation, while eight stations showed increases, with the strongest upward trends again seen at Punjabi Bagh and R K Puram.

Despite these improving trends, the report has cautioned that the magnitude of decline in the Capital remains small relative to the city’s high baseline pollution levels or pollution levels throughout the year.

More than 90% of monitoring stations across India, including most in Delhi-NCR, continue to exceed the annual National Ambient Air Quality Standards (NAAQS) for PM10.

Findings from across NCR reveal more consistent improvements in some cities with multiple monitoring stations. All stations with long-term data in Ghaziabad and Noida recorded statistically significant declines in both PM10 and PM2.5 levels, indicating more uniform improvements across these cities compared to Delhi, where trends vary sharply by location.

Beyond Delhi-NCR, the assessment finds that most cities with complete long-term data show declining particulate matter trends, but the picture is uneven. Among stations with at least five years of data, 44 recorded a statistically significant decline in PM10 levels, while 24 showed significant increases.

Cities with only one long-term monitoring station—such as Ahmedabad, Jabalpur, Jodhpur, Varanasi and Faridabad—showed significant declines, while significant “improving trends” were observed in cities including Amritsar, Asansol, Chandigarh, Kota, Ludhiana, Nashik and Thane, all of which also rely on a single monitoring station.

For PM2.5, 54 out of 89 stations with long-term data showed statistically significant declines, while 19 showed improvement. Cities such as Ghaziabad, Howrah, Hyderabad, Kolkata, Mumbai and Noida recorded consistent declines across all monitoring stations, whereas an improvement was observed in cities including Amritsar, Chandigarh, Chandrapur, Ludhiana and Thane.

The report has underlined that Delhi-NCR remains India’s most persistent pollution hotspot, even as trend analyses suggest gradual improvements at several locations. It also stresses that uneven monitoring coverage, particularly in cities with only one station, limits the reliability of citywide assessments, reinforcing the need for denser and more representative air quality monitoring networks under the NCAP.