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NEW DELHI: Delhi suffered its fifth consecutive ‘severe’ day on Wednesday, making it the longest streak of very hazardous air quality in the capital in three years. While visibility was markedly better and it was sunny for most part of the day, the Air Quality Index (AQI) improved from severe-plus level (460) on the previous day but remained in the severe zone at 419.
A longer stretch of severe days (including severe-plus) was last seen in Dec 2021 when the AQI was above 400 for six straight days.
Air quality is predicted to stay ‘severe’ on Thursday but may improve to ‘very poor’ on Friday and Saturday, according to the Air Quality Early Warning System for Delhi, which is the forecasting body under the Union earth sciences ministry.
However, with fog finally dissipating across the region, there’s hope the air quality may improve sooner. Signs of improvement were seen on Wednesday night as the city’s average AQI fell to 400 (in ‘very poor’ range) by 10pm.
In Nov so far, Delhi has witnessed seven severe days. Of these, the city has been reporting consecutive days of severe days since Nov 16, including two ‘severe plus’ days on Nov 18 and 19. With an AQI of 494, Nov 18 was the second most polluted day on record. In contrast, Nov last year saw nine severe days, but the longest consecutive streak was of four days. Dec 2023 saw three consecutive severe days. In 2022, Nov and Dec recorded a total of three and two severe days.
“Dry westerly and north-westerly winds are blowing in the region. These winds have thinned the layer of fog in north-west India, causing a rise in maximum temperature. The sun’s rays were able to break through the sky, which reduced the smog conditions and hence, there was a slight improvement in the air quality,” said Mahesh Palawat, vice president at Skymet Meteorology. Central Pollution Control Board’s data showed the AQI showed slight improvement throughout the day. It was 426 at 9 am and reached 419 at 4 pm but touched 405 at 8 pm.
The share of stubble burning in Delhi’s PM2.5 was 19.82% on Monday, according to the Decision Support System. The lowest visibility of 600 metres was recorded at Palam at 8.30 am, which improved to 700 metres at 9 am. It further improved to 1,200 metres at 12.30 pm. The maximum temperature rose to 26.8 degrees Celsius, one degree below normal, on Wednesday. The minimum temperature dipped to 11.2 degrees Celsius, one degree below normal, making it the season’s lowest so far.