Delhi’s air quality remains close to ‘very poor’ for 2nd day; rain expected
A haze of dust blanketed the region for nearly 12 hours from 10pm on Wednesday to Thursday before the air quality improved gradually after noon as the dust blew eastwards
Delhi’s air quality remained close to the “very poor” category for a second day on Friday after overnight dust-raising winds dipped visibility and deteriorated pollution levels to the “poor” zone on Thursday. Very light rain was expected to improve the situation later on Friday.
A minimum temperature of 26.2°C, or 0.3°C below the normal, was recorded on Friday compared to 25.4°C a day earlier. The mercury was expected to go up to 40-42°C. An air quality index (AQI) of 297 (poor) was recorded at 9am on Friday, compared to 292 (poor) at 4pm a day earlier.
A haze of dust blanketed the region for nearly 12 hours from 10pm on Wednesday to Thursday. The air quality improved gradually after noon as the dust blew eastwards. The visibility dipped from 4,500 metres at 10pm on Wednesday to 1,200 metres by 11:30 pm. A subsequent drop in wind speed maintained the elevated dust levels. The India Meteorological Department (IMD) had forecast thundery weather, catching people off guard.
The increased dust levels spiked the PM10 concentration. The hourly PM10 levels went up to 2,969µg/m³ at Najafgarh, according to the Delhi Pollution Control Committee data from 24 stations. The 24-hour safe standard for PM10 is 100µg/m³.
PM10 is inhalable particulate matter. With a diameter of 10 micrometers (0.01 mm) or less, it can enter the lungs and cause health problems.
A high north-south pressure gradient in northwest India led to the dust-raising surface winds of 30- 40 kmph in Punjab, Haryana, Delhi, and north Rajasthan from Wednesday night to Thursday morning. The IMD said strong winds carried dust from Rajasthan’s Thar desert to Punjab and Haryana, and Delhi.
An IMD official said partly cloudy skies might persist throughout on Friday. “There is a possibility of very light rain, thunderstorm, lightning, and gusty winds of 30-40 kmph. The wind speed might reach 50 kmph during the thunderstorm towards the [Friday] evening or night.”
A second IMD official said similar weather was expected on Saturday, with the possibility of very light rain, thunderstorms, and high wind speeds in the morning.
