By Kavita Mistry 
Delhi has once again emerged as the most polluted region in India, according to a new satellite-based analysis released by the Centre for Research on Energy and Clean Air (CREA). The National Capital Territory recorded an annual average PM2.5 concentration of 101 µg/m³ between March 2024 and February 2025 — more than 2.5 times India’s national limit and 20 times the WHO guideline.
The data underscores that India’s air pollution crisis continues to deepen, extending far beyond the capital.
What Is PM2.5 and Why It Is Deadly
PM2.5 refers to fine particulate matter with a diameter smaller than 2.5 micrometres — tiny enough to enter the bloodstream and damage vital organs. It is linked to:
- Heart disease
- Stroke
- Lung cancer
- Severe respiratory illnesses
- Reduced lung development in children
- Premature death
Major sources include vehicle emissions, coal plants, industry, biomass burning, and winter smog conditions that trap pollutants close to the ground.
While the WHO recommends just 5 µg/m³, India’s standard is 40 µg/m³ — yet most districts still fail to meet even this relaxed threshold.
Delhi Is Worst, But India’s Pollution Is Widespread
After Delhi, the analysis ranked:
- Chandigarh: 70 µg/m³
- Haryana: 63 µg/m³
- Tripura: 62 µg/m³
- Assam: 60 µg/m³
- Bihar: 59 µg/m³
In total, 447 out of 749 districts — 60% — exceeded national limits.
Some regions recorded 100% non-compliance, including:
- Delhi
- Punjab
- Haryana
- Assam
- Meghalaya
- Tripura
- Jammu & Kashmir
States like Bihar (37 of 38 districts) and West Bengal (22 of 23) showed near-uniformly high pollution levels.
India’s Pollution Problem Is Global in Scale
Global assessments back the severity of the crisis:
- 39 of the world’s 50 most polluted cities (IQAir 2023) were in India
- Delhi, Begusarai, Guwahati and New Delhi ranked as the world’s four most polluted cities
- India consistently ranks among the world’s top three most polluted countries
Whether measured through ground monitors or satellite data, the conclusion is the same: India is the global epicentre of PM2.5 pollution.
A National Crisis Demanding Urgent Action
The CREA report makes it clear that air pollution is not a seasonal or regional anomaly — it is a structural, nationwide public health emergency.
Experts say India now needs:
- Stronger inter-state coordination
- Rapid clean energy expansion
- Tougher industrial enforcement
- Better rural and remote monitoring systems
With India dominating global pollution rankings year after year, the latest satellite evidence adds fresh urgency to the fight for cleaner air and healthier cities.