As Delhi decks up for Diwali celebrations on October 20, weather conditions are aligning for yet another episode of post-festival smog. The India Meteorological Department (IMD) has predicted clear skies but worryingly low wind speeds — just about 5 kmph on Diwali night — conditions that could trap pollutants close to the surface and push air quality deep into the “severe” zone.
LOW WIND SPEEDS : TRAP FOR POLLUTANTS
Currently, winds in the National Capital Region (NCR) are hovering at 10 kmph. As per IMD prediction, if the air is too still, it will not help to disperse the smoke and pollutants.
The Commission for Air Quality Management (CAQM) has already activated Stage 1 of the Graded Response Action Plan (GRAP) after PM2.5 levels crossed the “poor” threshold of 200. In Noida, the AQI has surged past 318 — a worrying sign ahead of the festival.
DROP IN TEMPERATURE
Early Thursday morning, Delhi woke up to an AQI of 233 and a mild chill in the air with temperatures dipping to 18.2°C. IMD data shows that both maximum and minimum temperatures are slightly below normal, a typical pre-winter pattern that also contributes to pollutant accumulation by lowering the mixing height of the atmosphere.
IMD forecasts suggest no significant change in temperature through October 19, with calm winds in the early morning hours and only a brief increase to 10–15 kmph by afternoon. By Diwali night, wind speeds will drop again to 5–6 kmph, making it the perfect trap for particulate matter, smoke, and emissions.
With the onset of mist and shallow fog predicted for the weekend, Delhi’s festive lights may once again glow through a hazy, polluted veil — a reminder that there is going to be calm before the choke.
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