Delhi-NCR witnessed a sharp deterioration in air quality on Diwali night as thick smoke blanketed several parts of the region and visibility fell. Delhi’s overall Air Quality Index (AQI) stood at 373, in the “very poor” category, at 11:05 pm on November 8, according to data cited from the Central Pollution Control Board (CPCB).
Several parts of the capital, however, recorded AQI levels above 400, placing them in the “severe” category. Areas reporting such levels included Alipur, Bawana, Burari, Chandni Chowk, Mundka, Punjabi Bagh, Rohini and Vivek Vihar, among others.
Delhi-NCR air quality on Diwali night
The pollution was not restricted to Delhi. At 11:05 pm, Noida’s average AQI stood at 319, while Ghaziabad recorded 360. Gurugram and Faridabad recorded AQI levels of 280 and 297, respectively.
According to the CPCB classification, an AQI between 301 and 400 falls under the “very poor” category, while 401 to 500 is classified as “severe”.
The Air Quality Early Warning System had predicted that Delhi’s air quality was likely to remain in the severe category from November 9 for the next few days.
GRAP Stage 3 already in force
Ahead of Diwali, the Commission for Air Quality Management (CAQM) had enforced Stage 3 of the Graded Response Action Plan (GRAP) across Delhi-NCR as a pre-emptive measure.
The move came amid forecasts of worsening air quality around the festival.
Despite restrictions, concerns were raised over compliance with pollution-control measures and the continued use of firecrackers.
Environmentalist questions pollution data
Environmentalists also raised questions about whether official AQI readings fully reflected the pollution being experienced across neighbourhoods.
Environmental activist Bhavreen Kandhari questioned the reliability of government pollution data and pointed to differences between official readings and measurements from independent AQI monitors. She also raised concerns about data gaps at several monitoring stations on November 6.
Kandhari alleged that 11 monitoring stations had experienced data gaps, including 22 missing hourly PM2.5 readings and 27 missing PM10 readings. She specifically mentioned outages at IIT Delhi, Nangloi and NSIT Dwarka.
The concerns come as Delhi enters another period of severe winter pollution, with smoke, poor dispersion conditions and emissions contributing to deteriorating air quality.