Delhi Pollution After Diwali: Thick Smog Chokes Capital As AQI Stays ‘Very Poor’

Delhi’s Air Quality Index (AQI) stood at 366 as of 6.15 am on Monday, remaining in the ‘very poor’ category a day after Diwali, while several monitoring stations recorded readings in the ‘severe’ category, according to the Central Pollution Control Board’s (CPCB) Sameer app. ITO recorded an AQI of 406 at 4.20 am, while smog reduced visibility in parts of the capital, including Inderlok, ANI reported.

Delhi’s daily average AQI stood at 376 on Sunday, compared with 369 on Saturday. While the citywide reading remained in the ‘very poor’ category, several neighbourhood monitoring stations crossed the ‘severe’ threshold. Stage III of the Graded Response Action Plan (GRAP) has been in force across Delhi-NCR since November 6.

15 Monitoring Stations Record Severe AQI

The CPCB classifies an AQI of 301-400 as ‘very poor’ and 401-500 as ‘severe’. In the 7 am snapshot reported by Hindustan Times, Sonia Vihar recorded an AQI of 449, followed by Burari Crossing at 445 and Vivek Vihar at 441. Jahangirpuri recorded 439, North Campus 437 and Rohini 435. DTU registered 431 and Bawana 424.

Other stations in the same snapshot in the ‘severe’ category included Chandni Chowk and Patparganj at 418 each, Mundka at 413, NIH Narela and Punjabi Bagh at 408 each, and Commonwealth Sports Complex and ITO at 404 each. These are individual station readings, not the citywide hourly average.

ANI reported that ITO had recorded an AQI of 406 at around 4.20 am. It also reported a reading of 381 at Rajiv Chowk at 1.30 am and 360 in South Extension at around 4 am. The agency reported that smog had reduced visibility in parts of Delhi, including Inderlok.

A third-party air-quality ranking cited by Oneindia recorded an AQI of 2,552 in Sunder Vihar and 1,713 for Delhi overall at around 2 am on November 9. These figures were based on the US AQI system, which differs from the Indian National AQI used by the CPCB and has a standard reporting range of 0 to 500. Oneindia did not name the platform that provided the readings.

Firecracker smoke adds to pollution

Delhi’s air quality was already in the ‘very poor’ category before firecracker use increased on Sunday evening. PTI reported that the city’s AQI stood at 371 at both 7 pm and 10 pm. By 10 pm, 20 of the 59 monitoring stations were in the ‘severe’ category, while 33 were in the ‘very poor’ category and six in the ‘poor’ category. Sonia Vihar recorded 463 and Jahangirpuri 450.

PTI also reported that firecrackers were burst in areas including Pitampura, Burari, Mayur Vihar and Lutyens’ Delhi, despite restrictions. Residents reported reduced visibility and difficulty breathing.

An analysis by Hindustan Times of CPCB’s 15-minute data from 39 monitoring stations that also reported readings last Diwali found that average PM2.5 concentration rose from 190 micrograms per cubic metre in the 15-minute period beginning at 7.45 pm to 259 micrograms per cubic metre in the period beginning at 8 pm. For comparison, India's national 24-hour PM2.5 standard is 60 micrograms per cubic metre. The 259 micrograms per cubic metre figure is a 15-minute average and should not be treated as a direct comparison with the 24-hour standard.

The Decision Support System (DSS) projected that transport would account for 19 per cent of Delhi’s pollution on Sunday, while stubble burning was expected to contribute 3.5 per cent. Its projection for stubble burning on Monday was 2.99 per cent.

The Air Quality Early Warning System, operated by the Indian Institute of Tropical Meteorology, had forecast that Delhi’s air quality could deteriorate to the ‘severe’ category from November 9 and remain there for the following few days. It cited unfavourable weather conditions that could limit the dispersal of pollutants.

GRAP Stage III and separate CAQM curbs

The Commission for Air Quality Management (CAQM) invoked Stage III of GRAP across Delhi-NCR on November 6, based on forecasts of worsening air quality. The revised GRAP framework allows the CAQM to invoke measures in advance based on forecasts of worsening air quality, rather than waiting for the AQI to cross the threshold for a higher category.

Stage III measures include restrictions on specified construction and demolition activities, the closure of stone-crushing units and mining operations, and curbs on certain older vehicles in Delhi and designated NCR districts. The revised schedule also moved some diesel-generator measures from Stage II to Stage I; these are not new Stage III restrictions.

Separately, a CAQM order issued on October 30 put precautionary measures in place from November 5 to 20. It restricted specified dust-generating construction and demolition work across the NCR and directed government and private offices in Delhi and five NCR districts to limit physical attendance to 50 per cent, with the remaining staff working from home. The districts are Gurugram, Faridabad, Sonipat, Ghaziabad and Gautam Buddha Nagar. Certain essential services and establishments are exempt. These were time-bound precautionary directions, separate from the November 6 invocation of Stage III.

Supreme Court’s firecracker directions

The Supreme Court allowed certified green firecrackers in Delhi-NCR only between 6 am and 7 am and 8 pm and 10 pm on November 7 and 8. The permission ended on Sunday, with the complete ban on firecrackers restored from November 9. The court permitted manufacturers with valid CSIR-NEERI and PESO certification to produce only green crackers listed on the CSIR-NEERI website between November 2 and 6. Firecrackers containing barium, non-approved products and firecracker laris were prohibited.

The court also barred firecracker use within 300 metres of hospitals, nursing homes, primary and district health centres, old-age homes, educational institutions and notified silence zones. It observed that “bursting of firecrackers would certainly cause pollution”.

Speaking to ANI, Rashtriya Janata Dal MP Manoj Jha questioned the Centre and Delhi government's response to the recurring pollution crisis. “You wanted a triple-engine government, here it is. Shouldn't the Prime Minister and Amit Shah be questioned? I won't blame the Delhi CM alone,” he said.