Delhi’s air pollution has become a chronic public-health and governance crisis, especially in winter. On 4 November 2025, the city’s average AQI was 309 (“Very Poor”), with several hotspots like Jahangirpuri and Anand Vihar crossing 400 (“Severe”). November 2025’s monthly average (306) was worse than November 2024, indicating deterioration despite policy interventions. The problem is seasonal but rooted in deep structural causes across sectors and states.
The principal pollutant is PM2.5, with levels around 136 μg/m³, far above the WHO 24-hour guideline of 15 μg/m³. PM10 is also elevated, and secondary pollutants such as NO₂, SO₂, CO and O₃ compound the smog. Low wind speeds, a shallow boundary layer, and temperature inversion during winter trap these pollutants near the surface, causing recurrent smog episodes.
The AQI in India, calculated by CPCB using eight pollutants (PM10, PM2.5, NO₂, SO₂, CO, O₃, NH₃, Pb), shows Delhi oscillating between Poor and Severe categories for extended periods in winter. Governance arc
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