Delhi woke to thick smog on November 9, a day after Diwali, as air pollution surged following widespread firecracker use amid already poor air quality and unfavourable weather conditions. AQI.in recorded Delhi’s AQI at 1,331 at 1:31 am before it fell to 663 at 8:01 am, nearly 69% higher than the 393 recorded by the same platform on October 21, 2025, the day after Diwali last year.
However, the official Central Pollution Control Board (CPCB) data put Delhi’s citywide AQI at 368 at 7 am, in the ‘very poor’ category, with 15 of 54 monitoring stations reporting valid data recording AQI above 400, placing them in the ‘severe’ category. The deterioration came despite Stage III restrictions under the Graded Response Action Plan (GRAP), which the Commission for Air Quality Management (CAQM) had brought into force across Delhi-NCR from November 6.
Smog Follows Diwali Night
Pollution rose sharply through Sunday night, with AQI.in recording a reading of 681 at 9:31 pm before it crossed 1,000 by 11 pm and peaked at 1,331 at 1:31 am. The reading subsequently declined but remained at 663 at 8:01 am on Monday. Separately, CPCB data showed Delhi’s city-level AQI at 368 at 7 am, while 15 monitoring stations recorded ‘severe’ pollution.
Burari Crossing and Sonia Vihar recorded the highest station-level AQI at 441 each, followed by Vivek Vihar at 437 and Delhi Technological University at 434. PM2.5 was the prominent pollutant.
Pollution Built Up Earlier
Delhi’s air was already deteriorating before Diwali. AQI.in readings rose from 124 on October 30 to 393 on November 2 and 464 by November 3, after a brief improvement following late-October rain and stronger winds. As dry conditions returned, pollution from vehicles, industries, construction, road dust and waste burning accumulated.
The seasonal contribution from crop-residue burning in neighbouring states can also add to the particulate pollution load. Low wind speeds and poor atmospheric ventilation further limited the dispersal of pollutants. The Air Quality Early Warning System had forecast that Delhi’s air could enter the ‘severe’ category from November 9 and remain there over the following few days.
GRAP Curbs Already Active
The worsening air quality had prompted CAQM to invoke Stage III of GRAP across Delhi-NCR from November 6, adding stricter measures to those already operating under the first two stages. These include restrictions on non-essential construction and demolition, controls on certain older vehicles and additional curbs on industrial and other polluting activities.
Delhi had also introduced expanded winter pollution-control measures from November 1, including restrictions on the entry of non-BS-VI vehicles registered outside the capital, subject to exemptions, and enforcement of the ‘No PUC, No Fuel’ rule.
Firecracker Rules Were Limited
The Supreme Court had not imposed a blanket prohibition on green crackers throughout the Diwali period. It permitted certified green crackers on November 7 and 8, with bursting allowed only between 6 am and 7 am and 8 pm and 10 pm. The court also prohibited fireworks within 300 metres of specified hospitals, healthcare facilities, educational institutions, old-age homes and notified silence zones.
It directed that the complete firecracker ban in Delhi-NCR would return from November 9. Reports of firecrackers being burst beyond the permitted framework came as the city’s air was already heavily polluted.
Health Concerns Grow
The post-Diwali pollution has renewed concerns about exposure to fine particulate matter, particularly for children, older people and those with existing respiratory or cardiovascular conditions. CPCB’s classification places AQI between 301 and 400 in the ‘very poor’ category and 401–500 in the ‘severe’ category. The Air Quality Early Warning System has warned that unfavourable meteorological conditions could continue to hinder pollutant dispersal in the coming days.
A Crisis Beyond Firecrackers
The latest spike highlights the difficulty of treating Delhi’s winter pollution as a single-source problem. Firecracker smoke added to pollution already present in the atmosphere, while transport emissions, industrial activity, road dust, waste burning, crop-residue burning and weather conditions also influence the city’s air quality.
The contrast between the overnight AQI.in reading and official CPCB figures also underlines the importance of identifying the monitoring system and time of measurement when reporting pollution numbers.
The Logical Indian’s Perspective
Delhi’s post-Diwali smog should not become an annual cycle of blame, outrage and temporary restrictions. Firecrackers can add to the pollution burden, but the larger crisis demands sustained action on transport emissions, dust, waste burning, industrial pollution and regional sources, alongside responsible celebrations.
At the same time, conversations around pollution should avoid turning into attacks on communities or religious practices; protecting public health and respecting traditions can go hand in hand when citizens, governments and institutions work towards cleaner alternatives. What long-term measures do you think Delhi-NCR needs to ensure clean air is treated as a year-round priority rather than a post-Diwali emergency?
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