A recent analysis by the Health Effects Institute (HEI) has brought to light the severe air pollution crisis in Delhi and the National Capital Region (NCR). The report indicates that all of the top 20 most polluted air quality monitoring stations in India for 2024 are located in this area. It reviewed air quality trends following the launch of the National Clean Air Programme (NCAP) in 2019, revealing that while some locations show signs of improvement, the absolute pollution levels in Delhi-NCR remain alarmingly high.
The HEI report, titled “Assessment of Changes in Air Quality in Indian Cities Since the Launch of the National Clean Air Programme,” identified Jahangirpuri in North Delhi as the most polluted monitoring station in India for 2024. It recorded an annual average PM10 concentration of 276.1 µg/m³, significantly exceeding the National Ambient Air Quality Standards (NAAQS). PM10 refers to coarse particulate matter that poses serious respiratory and cardiovascular risks.
Long-term data presents a mixed but cautiously optimistic picture for Delhi. Analyzing raw PM10 data, 21 out of 27 monitoring stations showed declining trends, with reductions ranging from 0.3 to 9.7 µg/m³ per year. However, most of these declines were not statistically significant. Notably, some areas, such as Punjabi Bagh and R.K. Puram, exhibited increasing PM10 levels, indicating uneven progress across the city.
After accounting for seasonal and meteorological effects, researchers found that 19 stations demonstrated statistically significant declines in PM10 levels. The most pronounced reduction occurred at Jawaharlal Nehru Stadium, which saw a decrease of about 7.5 µg/m³ per year. For PM2.5, which consists of finer and more harmful particles, 22 stations exhibited declining trends, while 8 stations reported increases. Punjabi Bagh and R.K. Puram again showed the most significant upward trends. Despite these improvements, the report cautions that the rate of progress is minor compared to Delhi’s extremely high baseline pollution levels.
The study highlighted more uniform and substantial improvements in certain NCR cities outside of Delhi. In Ghaziabad and Noida, all long-term monitoring stations showed significant declines in both PM10 and PM2.5 levels, indicating more consistent progress compared to the varied trends observed in Delhi. This suggests local factors and targeted interventions play a crucial role in pollution control.
Across India, the air quality picture remains uneven yet slightly more encouraging. Among stations with a minimum of five years of data, 44 stations recorded significant declines in PM10, while 24 stations demonstrated significant increases. In terms of PM2.5, 54 out of 89 stations noted significant reductions. Cities such as Mumbai, Kolkata, Hyderabad, Howrah, Noida, and Ghaziabad showed consistent decreases in pollution levels. However, cities with only one monitoring station face challenges in reliability regarding city-wide assessments.
The National Clean Air Programme (NCAP) was initiated in 2019 by the Ministry of Environment, Forest and Climate Change to combat particulate pollution in Indian cities. The HEI report emphasizes that Delhi NCR continues to be India’s most persistent pollution hotspot. The uneven and sparse monitoring networks weaken assessment accuracy, underscoring the urgent need for denser, more representative air quality monitoring stations under NCAP.
Q1. What is the main finding of the HEI report on air pollution in Delhi-NCR?
Answer: The HEI report reveals that all top 20 most polluted air quality monitoring stations in India for 2024 are in Delhi-NCR, with Jahangirpuri being the most polluted station.
Q2. How does PM10 affect health?
Answer: PM10 refers to particulate matter that can penetrate the lungs, potentially leading to serious respiratory and cardiovascular issues, making air quality management crucial.
Q3. What improvements were noted in NCR cities compared to Delhi?
Answer: Ghaziabad and Noida showed more consistent declines in both PM10 and PM2.5 levels, contrasting with the varied trends in Delhi, demonstrating effective local interventions.
Q4. What challenges does the NCAP face in monitoring air quality?
Answer: The NCAP faces challenges from uneven and sparse monitoring networks, which impact the accuracy of air quality assessments and highlight the need for more stations.
Q5. How have PM2.5 levels changed in the monitored areas?
Answer: After adjusting for seasonal effects, 22 monitoring stations exhibited declining trends in PM2.5, although some stations still showed increases, indicating inconsistent air quality improvements.
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