Diwali 2021: Smog returns as pollution monitors fail to implement strict GRAP norms

PM2.5 and PM10 have recorded emergency levels in Delhi-NCR since November 5 midnight

By Vivek Mishra
Published: Friday 05 November 2021
The morning after Diwali 2021 in Delhi. Photo: Vikas Choudhary / CSE
The morning after Diwali 2021 in Delhi. Photo: Vikas Choudhary / CSE The morning after Diwali 2021 in Delhi. Photo: Vikas Choudhary / CSE

The national capital woke up to a smoggy and hazy morning November 5, 2021, the night after Diwali, with pollutant levels at record highs and residents complaining of a number of ailments.

“This was my first Diwali in Delhi. I have never seen such smog and pollution. My eyes are watery and I am experiencing difficulty breathing,” Abhishek Kumar, who lives in Delhi’s Mayur Vihar Phase III, told Down To Earth November 5. 

Official pollution monitors had not contemplated that air quality would worsen to emergency levels on Diwali night.

The monitors decided not to take emergency-level steps during a meeting of the committee in charge of implementing the Graded Response Action Plan (GRAP) November 3.

This measure was taken after experts at the meeting reached the conclusion that air quality in Delhi and the National Capital Region (Delhi-NCR) would not change from the ‘very poor’ category on Diwali day.

The Air Quality Index (AQI) represents 24-hour average air quality data. The air quality is considered to be ‘very poor’ when the AQI is from 301-400, according to Central Pollution Control Board (CPCB) guidelines.

An AQI of 0-50 is considered ‘good’, 51-100 ‘satisfactory’, 101-200 ‘moderate’, 201-300 ‘poor’ and 401-500 ‘severe’. Above 500 is the ‘severe-plus or emergency’ category.

Under GRAP, the Delhi administration is mandated to stop the use of diesel gensets, enhance parking fees by 3-4 times, increase Metro and bus frequency and use water sprinklers if the air quality is ‘very poor’.

It can stop the operations of brick kilns, hot mix plants and stone crushers and make power plants switch to natural gas instead of coal if the air quality is ‘severe’.

The air quality did deteriorate. The CPCB’s Central Control Room recorded Particulate Matter (PM)2.5 levels in Delhi-NCR to be 309 microgram per cubic metre (µg / m³) at 11.30 pm November 4. PM10 levels were recorded to be 500 µg / m³ at 3.30 am.

At 10.30 am November 5 morning, PM.25 levels had been in the emergency range for 11 hours while PM10 had been in the same range for eight hours.

PM2.5 in Delhi-NCR at 10.34 am was seven times the average level of 60 µg / m³ at 417 µg / m³. On the other hand, PM10 was six times its average level of 100 µg / m³ at 598 µg / m³.

At 10.5 am November 5, of the 39 pollution monitoring stations in Delhi, five were not working, five had recorded the air quality as ‘very poor’ and 29 had recorded it as ‘severe’.

The air quality in Delhi’s satellite towns was also ‘severe’ November 5 morning. 

AQI (At 8 pm on November 4) AQI (At 10.5 am on November 5)
Delhi 404 460
Ghaziabad 440 446
Noida 422 463
Rohtak 412 449
Gurugram 416 477
Faridabad 420 458
Panipat 401 449

Avikal Somvanshi, programme manager and expert at Delhi-based non-profit Centre for Science and Environment’s Sustainable Cities Programme, said:

The pollution monitors knew that Delhi-NCR’s air quality could become severe on Diwali night. It is unfortunate that steps were not taken accordingly. Given that the novel coronavirus disease (COVID-19) has already weakened the immunity of residents, norms in accordance with the ‘severe’ category should have been implemented.

The situation is expected to be worse November 5 and 6 because of the increase in stubble burning in Punjab, Haryana and western Uttar Pradesh as well as the drop in temperatures. It will begin to improve November 7, according to the Indian Institute of Meteorology, Pune.

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