50kmph winds clean Delhi’s air, Grap curbs scaled down

Delhi’s maximum will drop to 27°C by Wednesday and 25°C by Friday. Minimum will be between 10-12°C over the next three days, before dropping to 8°C by Friday

Strong and gusty surface winds swept the city, coursing at an average speed of 50km/houron Monday, owing to a western disturbance influencing the northern region, the India Meteorological Department (IMD) said, adding that similar conditions will prevail for the next two days in the Capital and maintain partially cloudy skies.

The city’s AQI is likely to remain between poor and moderate with light rain in the coming days. (Raj K Raj/HT photo)

Strong winds also helped filter out bad air further and brought it to the lower end of the “poor” category, with a reading of 231 at 4pm on Monday. It was 269 (poor) at the same time on Sunday and will likely improve to the “moderate” zone by Tuesday.

The improvement in air quality prompted the Commission for Air Quality Management (CAQM) in NCR to lift Stage 2 of the Graded Response Action Plan (Grap) immediately on Tuesday. Grap Stage 2 calls for preventive measures like sprinkling water on roads, mechanised sweeping, regular monitoring of construction and demolition sites and augmentation of bus and Metro fleet, to be implemented across Delhi NCR.

“The average AQI of Delhi has considerably improved in the last four to five days and remained below 300 from February 15. The forecast by IMD and the Indian Institute of Tropical Meteorology also indicates the average AQI of Delhi will stay between ‘moderate’ to ‘poor’ with light rain or drizzle in the coming days... keeping in view this improvement and forecasts in the coming days, the CAQM sub-committee has unanimously decided to revoke Stage 2 of GRAP,” CAQM said in a statement on Monday.

Stage 2 measures came into effect in Delhi NCR on October 21, 2023. Now, only Stage 1 measures of GRAP remain in place, which also includes preventive measures, ensuring construction and demolition waste is lifted regularly, deploying traffic personnel at congestion points for smooth flow of traffic, and ensuring DG sets are not used as a regular source of power supply.

Weather officials said strong winds were prevalent across the northern plains, with the highest wind speed touching around 50 km/hour at Palam, while the average speed was around 20-30 km/hr.

“It was 50 km/hour during the day, with average speed dropping to 30 km/hour in the afternoon. Wind speed will drop to 10-15 km/hour by Tuesday, but cloudiness will persist in the region. Showers expected in the Himalayan region, Punjab and parts of UP,” said Kuldeep Srivastava, scientist at IMD, adding that isolated places in Delhi NCR may record a drizzle on Tuesday.

The western disturbance also led to a sharp rise in Delhi’s minimum temperature, which was recorded at 14.1°C — three degrees above normal. This was Delhi’s highest minimum since November 4 last year, when it was 14.6°C. Delhi’s minimum a day earlier was 8.6°C.

Meanwhile, the maximum dropped marginally and was recorded at 28.2°C, four degrees above normal. It was 29.7°C on Sunday, which was the highest so far this year.

Forecasts by IMD show Delhi’s maximum will drop to 27°C by Wednesday and 25°C by Friday. The minimum is forecast to be between 10-12°C over the next three days, before dropping to 8°C by Friday.