Delhi’s air quality deteriorated sharply on Saturday, with the 24-hour average air quality index touching 199 — just one point shy of the “poor” category — as the Capital enters the pre-winter pollution season marked by stagnant winds and temperature inversions that trap pollutants near the ground.
The Air Quality Early Warning System forecast further deterioration, predicting poor air quality from Sunday through the week ahead, with conditions expected to worsen as Diwali approaches the next weekend.
Saturday’s AQI of 199 marked a significant jump from 170 on Friday and 100 the previous day, according to the Central Pollution Control Board’s daily bulletin.
The sharp rise reflects typical meteorological patterns for mid-October, when falling temperatures create atmospheric conditions that prevent pollutants from dispersing.
“The wind speed on Saturday was quite low, around 6-9 kmph. These are dry westerlies, which sometimes also bring dust with them, contributing to the city’s pollution level,” said Mahesh Palawat, vice president at Skymet. “The wind speed is expected to remain low for the next few days.”
Low wind speeds, combined with the onset of temperature inversion — where cooler air becomes trapped beneath warmer air — create a “lid” that concentrates pollutants near the surface. Northwesterly winds during this season also carry smoke from crop stubble burning in Punjab and Haryana. This time next weekend, if calm wind conditions persist, the air is also likely to include a toxic cocktail of smoke from firecrackers.
The Air Quality Early Warning System bulletin on Saturday evening warned that “air quality is very likely to be in the poor category from Sunday to Tuesday,” with the outlook for the subsequent six days also indicating poor conditions.
The timing coincides with Diwali preparations, with the festival just a week away. The Capital typically sees a sharp spike in pollution levels during Diwali due to firecracker burning, compounding the meteorological factors.
CPCB classifies air quality on a scale where 0-50 is good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor, and 401-500 severe.
Delhi last recorded poor air on June 11, when the AQI stood at 245. Since then, the capital has enjoyed 122 consecutive days of cleaner air — 77 satisfactory days and 45 moderate days, according to CPCB data.
Meanwhile, temperatures rose slightly on Saturday, with Safdarjung, representative of the city’s weather, recording a maximum of 30.3°C — 3.9°C below normal but higher than Friday’s 29.9°C.
The minimum temperature was 19.4°C, up from 18.8°C the previous day and 1.6°C below normal.
The India Meteorological Department forecast mainly clear skies for the coming week, which could push temperatures higher as more solar radiation reaches the earth’s surface. Maximum temperatures are expected to rise to 31-33°C by Monday and 32-34°C by Wednesday, while minimums could touch 20-22°C by midweek.