Delhi’s air quality may improve further; light rain, stronger winds to help

At 9 pm on Wednesday, the average AQI at several monitoring stations including at ITO, Mandir Marg, RK Puram, Lodi Road and Patparganj was in the ‘moderate’ zone.

Strong winds and clear skies helped Delhiites breathe easy on Wednesday, as the air quality finally improved to enter ‘poor’ category on the air quality index after remaining in the ‘severe’ and ‘emergency’ zone for nearly a week. Scientists at the India Meteorological Department (IMD) have forecast that the air will further improve in the coming days.

A view of India Gate and Akshardham Mandir on a clearer day on Wednesday. The buildings in the national capital remained enveloped in a thick haze for the past one week as air quality had deteriorated post-Diwali. (Amal KS/HT PHOTO)

The AQI for Delhi has improved from 407 on Monday to 324 on Tuesday and 214 on Wednesday, as per CPCB data.

“At 2 pm today, PM 2.5 – 39, PM 10 – 96. I am glad pollution is coming down. We have to keep up our efforts so that coming days do not see any spike. Grateful to everyone whoever made efforts to reduce it, (sic)” Delhi chief minister Arvind Kejriwal tweeted on Wednesday.

IMD scientists said higher wind speed helped clear pollutants, adding that air quality in the national capital is expected to improve further in the coming days. “The average wind speed throughout the day was 12kmph, which helped blow away the pollutants. The sky was also clear today (Wednesday) and there was good sunlight. The increase in temperature also helped improve the air quality,” said Kuldeep Srivastava, head of the IMD’s regional weather forecasting centre.

Another scientist from IMD, who did not wish to be named, said that the situation is likely to improve further from Thursday. He said the air quality is likely to remain in the ‘moderate’ range till Sunday. AQI in the range of 0-50 is considered ‘good’, 51-100 ‘satisfactory’, 101-200 ‘moderate’, 201-300 ‘poor’, 301-400 ‘very poor’ and 401-500 ‘severe’.

“Tomorrow (Thursday) there is a forecast of strong winds, so there will be some more improvement in the air quality. The direction of the winds on Wednesday was also easterly, which means that the residue from stubble burning in Punjab and Haryana did not affect Delhi,” the senior IMD scientist said.

He added that even though shallow fog expected on Thursday morning, it will not play a major role in trapping pollutants as the winds will be strong and consistent through the day. There is also a possibility of light rain in some parts of the city, which will also bring relief.

At 9 pm on Wednesday, the average AQI at several monitoring stations including at ITO, Mandir Marg, RK Puram, Lodi Road and Patparganj was in the ‘moderate’ zone.

In fact, the PM 2.5 (fine particulate matter with a diameter less than 2.5 micrometres) levels showed a downward curve till 11am and increased marginally to reach 110ug/m3 at 7pm. Data by System of Air Quality and Weather Forecasting and Research (SAFAR), ministry of earth science’s weather and air quality monitoring centre, also showed that on Wednesday, stubble burning from neighbouring states contributed to only 3% of Delhi’s PM 2.5 levels.

Delhi has been experiencing the worst air days since Diwali on October 27, when the AQI levels nosedived to reach 337. The situation progressively became worse since then and on October 30, Delhi recorded its first ‘severe’ air day.

On Friday, a public health emergency was declared in the city. Measures such as the closure of schools and a blanket ban on construction activities had to be imposed.