Strong winds keep AQI at ‘moderate’ in Delhi, minimum at 6.9°C

Strong and gusty winds coursing through the city on Wednesday kept bad air at bay for the third consecutive day, with the 24-hour average air quality index (AQI) settling at 175 (moderate) at 4pm, according to the Central Pollution Control Board’s (CPCB) national bulletin.

Wednesday’s AQI was a marginal rise from Tuesday’s 141, but better than 180 on Monday. This three-day streak of moderate pollution levels is Delhi’s best air spell since October last year, when the air was also moderate for four straight days.

The relief from noxious air has come after a gap of over 100 days in the Capital — when it was 121 (moderate) on October 19, 2023.

According to weather officials, even though the winds blowing in from the mountains of the northwest gained momentum on Wednesday, temperatures were largely unaffected. The minimum temperature was recorded at 6.9°C, three below normal, as compared to 7°C on Tuesday. Meanwhile, the maximum was at 20.7°C, a marginal dip from 21°C on Tuesday.

“The wind speed throughout the day stayed between 25-35 km/hour and this helped keep the skies mostly clear, with occasional clouds. But the clouds were not stagnant and kept clearing out,” said Kuldeep Srivastava, a scientist at the India Meteorological Department.

IMD has forecast mainly clear skies with strong surface winds with a speed between 25 to 35 km/hour through Thursday as well.

“There might be strong gusty winds along with the surface winds, of up to 45 km/hour on Thursday. The minimum should stay around 7°C till Friday and then gradually increase while the maximum will stay around 21°C on Thursday, before rising,” said a Met official.

Pollution levels would also likely stay in the “moderate” category, officials said. Forecasts by the Early Warning System (EWS) for Delhi, an air quality forecasting model under the ministry of earth sciences, shows that a similar air quality is expected for the next two days.

“The air quality is likely to be in ‘moderate’ category till Friday and deteriorate to ‘very poor’ on Saturday. The outlook for the subsequent six days shows air quality is likely to be in the ‘very poor’ to ‘poor’ categories,” said EWS in its daily bulletin on Wednesday.

According to Srivastava, the strong winds also helped keep the early hours of the day free of any fog. “It is unlikely that there will be any fog on Thursday as well, owing to the surface winds. Even if there is, it will be very shallow and visibility will not be affected,” he added.