Days before strict anti-pollution measures kick in, air quality dips to 'very poor' at many places in Delhi-NCR
There was a visible improvement in the national capital's air quality on Monday afternoon as winds gusting up to 20 kilometres per hour dispersed some of the noxious haze that lingered over Delhi for around a week, even as the city's pollution level still remained in the 'severe' category.
The India Meteorological Department (IMD) said Cyclone Maha and a western disturbance will cause rainfall in parts of the northern plains, covering Rajasthan, Punjab, Haryana, western Uttar Pradesh and Delhi-NCR, on Wednesday and Thursday which will improve the situation further.
Though there was a significant, visible change in pollution levels on Monday, the national capital's air quality index (AQI) at 4 pm read 416, which is still in the 'severe' category, according to the Central Pollution Control Board (CPCB).
CPCB's former director Dipankar Saha said this is because the air quality index reading at any given time is an average of AQIs recorded in the previous 24 hours.
Weather experts said a significant increase in the wind speed dispersed the pollutants faster.
The cloud cover over Delhi and the neighbouring areas also dissipated, revealing the sun that caused the air close to the ground to rise up and flush out pollutants.
Kuldeep Srivastava, a senior scientist at the IMD, said, "The two main reasons for improvement in air quality are increased wind speed and no cloud cover."
On Sunday, the pollution levels in the city peaked to a three-year high of 494, the highest since November 6, 2016 when it was 497.
Mahesh Palawat of Skymet Weather, a private forecaster, said rainfall is likely in Delhi and neighbouring areas on November 6 and 7 under the influence of Cyclone Maha.
"A western disturbance will also increase the wind speed... Strong easterly winds due to Cyclone Bulbul will reduce the impact of smoke from stubble burning in (Haryana and Punjab)," he said.
In the National Capital Region (NCR), Noida (446), Ghaziabad (464) and Greater Noida (444), Gurgaon (396), Faridabad (414), also recorded improvement in air quality.
An AQI between 0-50 is considered 'good', 51-100 'satisfactory', 101-200 'moderate', 201-300 'poor', 301-400 'very poor' and 401-500 'severe'. Above 500 falls in the 'severe plus' category.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)