Overview
- Citywide AQI stayed in the very poor range at the turn of the year, with readings around 371–380 and several stations in the severe bracket, including Anand Vihar near 421–423.
- IMD issued cold wave alerts for January 2–5 and warned dense to very dense fog is likely through January 6, after visibility fell to about 50 metres at Safdarjung and Palam during early hours.
- Flight operations were heavily disrupted, with Delhi airport reporting about 150 cancellations and hundreds of delays, and airlines issuing advisories and pre‑emptive cancellations for low visibility.
- Officials attributed the spike to an unfavourable ventilation index below 6,000 m²/s and weak winds under 10 km/h that are limiting pollutant dispersion across Delhi‑NCR.
- CPCB data show Delhi’s 2025 PM2.5 average edged down to roughly 95 µg/m³ due to an exceptionally wet monsoon, even as December averaged about 207 µg/m³ and analysts flagged monitoring gaps and data quality concerns.