Air pollution: Delhi's air quality 'severe' again, no respite likely anytime soon

Residents in Delhi continued to struggle with unhealthy air on Friday as the air quality turned "severe" again with a dip in temperatures and slow wind speed at night allowing accumulation of pollutants.

At 8 am today, the city's air quality index (AQI) stood at 401.

Air quality in Anand Vihar was reported to be "severe" category at 418. RK Puram, on the other hand, had an AQI of 424 and Patparganj's AQI stood at 416 as at 8 am, according to Central Pollution Control Board (CPCB) data.

After a slight improvement on Sunday, Delhi has been witnessing a gradual increase in AQI levels.

The 24-hour average AQI, recorded at 4 pm every day, was 390 on Thursday, 394 on Wednesday, 365 on Tuesday, 348 on Monday and 301 on Sunday.

An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate", 201 and 300 "poor", 301 and 400 "very poor", 401 and 450 "severe" and above 450 "severe-plus".

Earlier on Saturday, the Centre removed stringent curbs, including a ban on construction work related to linear projects and the entry of polluting trucks in Delhi, following a drop in pollution levels due to a favourable wind speed and direction.

As per the air quality early warning system developed by the Pune-based Indian Institute of Tropical Meteorology, pollution levels are likely to oscillate in the "very poor" to "severe" categories in the next five to six days.

Vehicular emissions accounted for about 38 per cent of the capital's air pollution on Thursday, data from a joint project by the Delhi government and the Indian Institute of Technology (IIT), Kanpur, revealed.

Secondary inorganic aerosols -- particles such as sulfate and nitrate that are formed in the atmosphere due to the interaction of gases and particulate pollutants from sources like power plants, refineries and vehicles -- are the second major contributor to Delhi's foul air, accounting for 25 to 35 per cent of the air pollution in the city over the last few days.

(With PTI inputs)

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