Weather comes to Delhi’s rescue, winds flush out pollution
Good winds helped Delhi breathe relatively cleaner air on Thursday as the air quality index (AQI) improved to the lower end of the ‘very poor’ zone after remaining in the ‘severe’ zone for a day.
The air quality may improve to the ‘poor’ category by Friday and continue to remain so at least over the next three days, government agencies have forecast.
According to the Central Pollution Control Board’s (CPCB) 4 pm bulletin, the average AQI stood at 302 compared to 413 on Wednesday and 379 on Tuesday.
The levels of particulate matter (PM) also came down significantly. On Thursday evening, the PM 10 (coarse dust particles) levels reduced to 218ug/m3 as compared to 410 ug/m3 at the same time the previous day. The PM 2.5 levels (the most harmful aerosols in Delhi’s air) also came down to133 ug/m3 from 243ug/m3 on Wednesday.
Scientists at the India Meteorological Department (IMD) said the improvement was mainly because of a change in the wind direction and speed. Traces of rain were observed at the Lodhi Road and Ridge weather stations. Safdarjung Observatory -- the official marker for the city’s weather -- did not record any rainfall.
V K Soni of IMD’s environment monitoring research centre said that with the impact of stubble burning being almost negligible, the good winds helped in the dispersion of local pollutants.
“The wind speed was around 10-12 kmph. The wind direction changed to northwesterly in the afternoon from easterly. We expect the wind speed to remain high over the next three days. The air quality is likely to improve to the ‘poor’ zone and will remain so at least till November 30,” Soni said.
According to the System for Air Quality and Weather Forecasting and Research (SAFAR), the union ministry’s air quality forecasting wing, the share of stubble burning to city’s PM 2.5 levels on Thursday was just around 1% with the number of fire counts being as low as 37.
The IMD had also predicted cold wave conditions in Delhi from November 27. “Due to the influence of a western disturbance over Afghanistan and neighbouring areas, fairly widespread rainfall and snowfall, as well as isolated hailstorms, are likely over Jammu and Kashmir, Ladakh, Gilgit-Baltistan, Muzaffarabad and Himachal Pradesh from November 25, which will result in low temperatures in Delhi as well,” said Kuldeep Srivastava, head of IMD’s regional weather forecasting centre.
He said the minimum temperature is likely to remain around 6-7 degrees C till November-end. “The skies will be clear again, and this will cool the surface down faster and reduce the temperature by the end of the week,” said Srivastava.
On Thursday, the minimum temperature was 10.4 degrees C, a notch below normal. The maximum settled at 25.8 degrees C, normal for this time of the year.