The average air quality index (AQI) in Delhi was reported to be inching close to ‘Severe plus’ levels even as the highest anti-pollution curbs under the Graded Response Action Plan (GRAP) Stage 4 kicked in Monday morning to combat the rising pollution. At 6 pm, as per the Central Pollution Control Board (CPCB) data, the AQI was 494. According to experts, this is among the most polluted episodes observed in November in recent years. The average pollution levels on Sunday were the worst for October to November since 2022.
The data from CPCB showed that the hourly average PM2.5 and PM10 levels have been on a sharp increase since Sunday noon. The average PM2.5 level was 354 micrograms per cubic metre, which is more than 20 times the standard prescribed by the World Health Organization (WHO). The PM10 levels were also above the threshold by around 12 times the WHO standards. These are the highest pollution levels so far this season. The 24-hour average should be limited to 15 micrograms per cubic metre for PM2.5 and 45 micrograms per cubic metre for PM10 as per WHO.
Among the 38 functional air quality monitoring stations in Delhi, the most pollution was reported in Dwarka and Najafgarh with an AQI of 500 as of 11 am on Monday. All the stations reported air quality in the ‘severe’ category, breaching the 400 mark, and it was inching close to 500.
Sunil Dahiya, founder and lead environmental analyst at Envirocatalysts said, “The pollution levels observed in the last one week are the highest over the past five years. The rise in the pollution levels can be attributed to insignificant systematic actions on perennial pollution sources coupled with increasing stubble burning contribution in the past week and deteriorating meteorology. The PM2.5 concentration observed yesterday is 429 micrograms per cubic metre which is the highest observed concentration over the last week, compared to the same period since 2020.”
The average PM2.5 levels from November 11 to 17 were 297 micrograms per cubic metre in 2020 and 201, 258, 151, 225 and 304, respectively till 2024.
The CPCB data shared by Envirocatalysts showed that the 24-hour average PM2.5 level over Delhi on Sunday (November 17) at 429 micrograms per cubic metre was the highest since 2021 for October to November. This was the highest for this period compared to previous years, since November 10, 2022, when the average PM2.5 level was reported at 452 micrograms per cubic metre.
According to an air quality forecast by the Indian Institute of Tropical Meteorology (IITM), the air quality is likely to be in the ‘Severe’ or ‘Very poor’ category for the next six days.
GRAP 4 measures
Under Stage 4 of GRAP, the government has banned all construction and demolition activities with exceptions made for specific projects related to defence, Metro, railways, airports, and healthcare facilities. The eight-point action plan also includes a ban on the entry of diesel-powered medium and heavy vehicles (BS-IV and below) in Delhi, except those transporting essential goods or providing emergency services. Chief Minister Atishi has also announced that all schools will hold online classes for students, barring those in classes 10 and 12, until further orders.
IMD issues yellow alert
Meteorological conditions along with emissions – domestic and regional – cause a spike in pollution levels around this time of the year. The India Meteorological Department (IMD) has issued a yellow alert, forecasting moderate or shallow fog or smog conditions in the evening to nighttime.
Similarly, there is a yellow alert on Tuesday as well with the Met Office forecasting dense fog conditions in the morning with shallow or moderate fog for the later part of the day. From November 20 to November 24, it expects fog conditions to improve.
The weather bulletin by the IMD, as of 9.15 am on Monday, said dense fog was reported in Palam and the visibility was lowest at 100 metres till 8 am. Similarly, Safdarjung airport recorded the lowest visibility at 150 metres up to 3 am. The atmospheric conditions in the capital are not favourable for the dispersal of pollutants.
With a slight fall in temperatures over Delhi, the maximum and minimum temperatures are in the range of 28 to 30 degrees Celsius and 12 to 17 degrees Celsius, respectively. Westerlies with low wind speeds of 6 to 8 kmph prevailed with smog conditions over Delhi, said the IMD.
