With dust continuing to bring down city’s air quality, rain and strong winds on Monday offered some respite.
Delhi’s air quality, which was recorded in the ‘very poor’ category on Sunday as well as Monday, took a turn for the better on Monday evening. According to officials at India Meteorological Department, the much awaited showers, albeit light, meant that the concentration of particulate matter in the air dipped, improving air quality.
At the RK Puram air quality monitoring station for example, PM 10 concentration, which should be below 100 micrograms per cubic metre, was recorded at 537 µg/m3 at 6 pm. After the thundershowers, it dipped to 145 µg/m3 at 10 pm.
Similarly, at the Sri Aurobindo Marg air quality monitoring station, the concentration of PM 2.5 improved from 301 µg/m3 at 8 am to 17 µg/m3 at 10 pm. The standard for PM 2.5 is 60 µg/m3.
According to officials at the IMD, the reason behind the rain and thundershowers is an active western disturbance over Himachal Pradesh. “The whole of this week is expected to see light rain or thunderstorms. The month of May is also when these occurrences are more common because of the interaction of hot air in the area with any cooler wind system that enters it. The clash of the two systems – local and regional – leads to thunder and dust storms,” said an IMD official.
While the wind is coming in from the West, where crop residue burning has been picking up over the last few days, officials said that the impact was not significant on air quality yet.
“In Delhi, the haze and poor air quality is primarily because of dust. Since rain has eluded the area for the past 10 days at least, there is a lot of loose dust that is being picked up by the wind. With rain, we expect the air quality to improve Tuesday onwards,” said an IMD official.