Delhi’s air quality worsened to the poor category on Wednesday, with the city recording an Air Quality Index (AQI) of 229 as slower winds allowed pollution levels to rise. Rain forecast for Thursday and Friday is expected to provide temporary relief, according to the India Meteorological Department (IMD) and the Air Quality Early Warning System.
The Central Pollution Control Board’s data showed that Delhi had its fourth poor air day of the month on Wednesday. The city had earlier recorded three consecutive poor air days from October 21 to 23, after which Stage I of the Graded Response Action Plan was imposed on October 21.
Air quality subsequently remained in the moderate category for four days from October 24 to 27 as stronger winds and rain helped disperse pollutants. With wind speeds declining on Wednesday, the AQI deteriorated again. Vivek Vihar was Delhi’s most polluted monitoring station, recording an AQI of 313 at 6pm.
The contribution of stubble burning to Delhi’s PM2.5 concentration stood at 0.9% on Wednesday, indicating that the recorded deterioration was not primarily attributed to farm-fire emissions in the information available from the source. Delhi’s AQI had been 197 on Tuesday, placing it in the higher range of the moderate category.
The Air Quality Early Warning System, which operates under the Union Ministry of Earth Sciences, forecast that Delhi’s air quality would remain moderate from Thursday to Saturday. The forecast coincides with an IMD yellow alert for light to very light rain at most places and moderate rain at isolated locations on Thursday.
The rain may be accompanied by thunderstorms, lightning and gusty winds reaching up to 50 kmph. Light to very light rain is expected on Friday. These weather conditions are likely to affect both pollution dispersion and daily movement across the capital, although the supplied forecast does not establish how long any improvement in air quality will last.
The IMD expects maximum temperatures to fall by 2 to 4 degrees Celsius over the next two days because of rain and cloud cover. The maximum temperature was 31.8 degrees Celsius on Wednesday, one degree above normal, and is forecast to remain between 26 and 28 degrees Celsius on Thursday and 27 and 29 degrees Celsius on Friday.
Minimum temperatures have also begun to shift. The temperature at Safdarjung rose marginally from the season’s low of 15.3 degrees Celsius on Tuesday to 15.7 degrees Celsius on Wednesday and is expected to rise over the next two days. Aya Nagar in southwest Delhi recorded the lowest minimum temperature at 14.8 degrees Celsius.
The next assessment of Delhi’s air quality will depend on how rainfall and wind conditions develop through Friday, alongside readings from the city’s monitoring stations and the Air Quality Early Warning System.
