India’s air quality management needs comprehensive pollution data that includes rural, peri-urban, and smaller cities, not just large metropolitan areas. Satellite-based PM2.5 monitoring provides consistent, high-resolution data to assess air pollution across states, districts, and airsheds. While ground monitoring under the National Clean Air Programme (NCAP) and National Air Quality Monitoring Programme (NAMP) is growing, it remains uneven and focused mainly on urban centers, missing key exposure areas elsewhere.
Satellite estimates, combined with ground data and atmospheric models, fill these gaps by providing consistent coverage that captures pollution hotspots, regional trends, and pollution transport beyond administrative borders. This approach supports more accurate assessments of exposure inequalities at the district level and identification of common pollution sources across airsheds like the Indo-Gangetic Plain.
In this assessment, we use satellite-derived PM2.5 estimates generated using the machine-learning framework of Kawano et al. (2025). Daily gridded values are aggregated into annual and seasonal means, and population data from NASA SEDAC’s GPWv4 are used to compute population-weighted PM2.5 levels.
The findings from this satellite-based PM2.5 assessment offer important insights for policymakers, helping to guide targeted interventions, plan resource allocation to the most affected regions, and support coordinated efforts across states. This report presents a detailed analysis of annual and seasonal PM2.5 concentration across states, districts, and airsheds, serving as a basis for informed policy decisions and tracking progress toward cleaner air.
Figure 6: Seasonal compliance of airsheds
Key Findings
District level
- 60% of India’s 749 districts breach the annual National Ambient Air Quality Standard (NAAQS) of 40 µg/m³, with no district meeting World Health Organisation (WHO) PM2.5 guideline of 5 µg/m³.
- Delhi, Tripura, Punjab, Haryana, Himachal Pradesh, Meghalaya, and Chandigarh maintained 100% district-level exceedance in all seasons except for monsoon.
- The top 50 most polluted districts are mostly concentrated in four states (Delhi, Assam, Haryana, and Bihar), indicating clear opportunities for targeted interventions.
State level
- All 33 states and union territories considered in the report exceed the WHO guideline, with 28 states also breaching India’s NAAQS.
- Delhi ranked as the most polluted state/union territory with an annual mean population weighted PM2.5 concentration of 101 µg/m³, 2.5 times the NAAQS and 20 times the WHO guideline.
- State-level PM2.5 averages can mask several local hotspots. For example, Maharashtra’s annual population weighted PM2.5 average was below the NAAQS, but 14 districts exceed the NAAQS, including Chandrapur due to dense clusters of coal-based industries and power plants.
Airshed level
- The Indo-Gangetic airshed remains the most polluted region in the country, consistently non-compliant during winter, summer, and post-monsoon season.
- An emerging concern is the Northeast airshed’s year-round air quality challenges, with Assam and Tripura maintaining elevated PM2.5 concentrations throughout the year.
- Most airsheds were below PM2.5 standards during the monsoon due to atmospheric cleansing, except the Assam–Tripura airshed. But the quick return to non-compliance post-monsoon shows that baseline emissions, not meteorology, are the real problem.
