Core Findings
- 60% districts (447/749) record annual PM2.5 above NAAQS (40 µg/m³).
- 0 districts meet WHO guideline (5 µg/m³).
- Indicates year-round exposure, not only winter-linked.
Relevance:
GS3 – Environment
- India-wide PM2.5 exposure trends; compliance gap with NAAQS/WHO standards.
- Seasonal divergence (winter vs monsoon) → atmospheric science relevance.
- Urban–rural health burden; link to climate–pollution interactions.
GS2 – Governance
- Air quality regulation, monitoring deficits, federal coordination challenges.
- Policy gaps in Clean Air Programme, emission control, district-level planning.
Geographical Pattern
- Major hotspots (Top 50 districts)
- Delhi – 11
- Assam – 11
- Bihar – 7
- Haryana – 7
- UP – 4
- Tripura – 3
- Rajasthan – 2
- West Bengal – 2
- Cleaner States (mostly within NAAQS)
- AP, Telangana, Kerala, Sikkim, Goa, Karnataka, Tamil Nadu
- Indicates North–East and North dominance vs South–Coastal cleaner belt.
Seasonality
- Winter (Dec–Feb)
- 82% districts (616/749) exceed NAAQS.
- Reasons: stable atmosphere, low wind, increased emissions.
- Monsoon (Jun–Sep)
- 90% districts within safe limits (675/749) due to rain scavenging.
Technical Notes
- PM2.5 = toxic chemical + organic aerosol particles.
- Population exposure differs from ambient readings due to population density distribution.
- Study by Centre for Research on Energy and Clean Air (CREA); not peer-reviewed.
