Delhi Air Pollution: Hopes of relief dealt another severe blow

NEW DELHI: The city's air quality relapsed to severe by Friday evening after staying in the very-poor range till afternoon. The air quality index (AQI) was 373 at 10am. In the absence of strong winds, it saw a marginal deterioration to 379 by noon, reaching 388 by 3pm, 393 by 4pm, and 401 by 6pm.

On Friday, the city got variable winds from westerly, north-westerly and easterly directions, with speeds ranging from 2-6 kmph, accompanied by shallow fog and smog in the morning. These conditions, coupled with low temperatures — 11 degrees Celsius at the minimum and 27.2 maximum — led to accumulation of pollutants through the day.

The average AQI at 4pm was in the upper level of the very poor range at 393, against 371 a day earlier.

The city was the most polluted in the region. Neighbouring Greater Noida saw an AQI of 262 (poor), Noida 312 (very poor), Gurgaon and Ghaziabad 302 (very poor), and Faridabad 292 (poor).

While the city continues to be under GRAP-IV restrictions and the fog layer has moved out, the share of most of the pollution sources remained almost the same. On Thursday, stubble burning contributed 17.9% to the net pollution, while local transport caused 18.2%, turning out to be the highest polluter.

According to the air quality early warning system by IITM, Saturday may see predominant surface wind from the west direction with speeds less than 4 kmph during morning hours, thus allowing the formation of smog or shallow fog in the morning, evening and night. The wind speed will further increase to 6 kmph from the northwest direction during the afternoon and again decrease to less than 4 kmph from the northwest direction during the evening and night.

The IITM expects AQI to remain very poor. "The ventilation index lower than 6,000 m2/s with average wind speed less than 10 kmph is unfavourable for the dispersion of pollutants. The air quality is likely to be in the very poor category from Nov 23-25," IITM said. In the subsequent 6 days, too, the AQI is likely to be very poor.

The PM2.5 level in the city on Thursday until 7pm oscillated between 160.9 and 196.8 micrograms per cubic metre, against a 24-hour national standard of 60 micrograms per cubic metre, and 15 units according to WHO standards.

The PM10 levels hovered between 281.7 and 327.2 micrograms per cubic metre, against a national standard of 100 units and 45 units as per WHO standards.

Delhi environment minister Gopal Rai has written to the Delhi chief secretary asking him to personally ensure that GRAP measures are adhered to properly.

"All the departments must submit daily reports on their actions and progress in implementing GRAP guidelines. This data will be critical for monitoring the effectiveness of measures and identifying areas requiring additional focus. The enforcement mechanisms being followed by various departments must be further intensified. Strict penalties should be imposed on violators of pollution control norms, including unauthorised construction and demolition activities, open burning of waste, burning of Parali, and other activities contributing to air pollution," Rai wrote.

Gurgaon's air quality, meanwhile, slipped into 'very poor' zone after staying in the 'poor' category for a day.

Experts attributed the deterioration to low wind speed, which did not allow the dispersal of pollutants.

Gwalpahari station recorded an AQI of 354, marking it as the most polluted area. This station covers the Gurgaon-Faridabad road, Golf Course road, and several highrises.

After a brief improvement, air quality in Noida and Ghaziabad, too, worsened in the ‘very poor' category.


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