Air quality index hit ‘severe’ levels despite claims that ‘green’ fireworks reduce pollution
Weather played no role in the spike, say meteorologists
Noise and air quality norms flouted across hospitals and neighbourhoods
Experts call for Supreme Court rethink as pollution control board cites ‘indiscriminate’ firecracker use
Kolkata’s air pollution soared to ‘severe’ levels on Diwali night despite the supposed use of ‘green fireworks’, allowed by the Supreme Court of India to cut firework-related pollution. Data showed the city’s air quality deteriorated sharply to ‘severe’ close to midnight, even though weather conditions remained stable, ruling out meteorological factors as a cause.
According to figures accessed by this correspondent, pollution levels across most automatic monitoring stations in the city rose dramatically from 8 pm onwards, which was the court-stipulated window for fireworks, and the incessant bursting continued well past midnight.
On Diwali night, nearly half of the 50-odd complaints received by the West Bengal Pollution Control Board were lodged after 8pm, underlining how violations continued unabated well beyond the court-stipulated deadline for bursting fireworks.
Experts from the green platform Sabuj Mancha found that the noise norms were flouted across all hospitals, which are designated as ‘silent zones’. A former West Bengal Pollution Control Board official said this Diwali was the “noisiest” since a 1996 Calcutta high court verdict first triggered legal action against noise pollution in the state. That ruling later became the basis for the national noise rules.
State Pollution Control Board chairman Kalyan Rudra attributed the pollution surge to the “indiscriminate use of expensive firecrackers”, while Kolkata Police Commissioner Manoj Verma admitted “a few violations” but claimed that the city “fared better than other metropolises”, saying both air and noise pollution levels were lower than last year.
“Clearly, the experiment with green fireworks has failed and the Supreme Court must rethink its firework strategy,” said Dr Dulal Bose, one of India’s foremost ear-nose-throat (ENT) specialists and a former sheriff of Kolkata. “Too many people’s health — including that of children, the elderly and the already ill — is at stake.”
The data tells its own story.
At midnight before Diwali (October 19-20, 2025), Kolkata’s average Air Quality Index (AQI) was 127 at, a ‘moderate’ level based on readings from seven monitoring stations. By Diwali midnight, the AQI had soared nearly 3.5 times to 434, entering the ‘severe’ category — the poorest air quality status measurable — which, according to the Central Pollution Control Board (CPCB), “affects healthy people and seriously impacts those with existing diseases”.
Air quality improved to ‘poor’ (266 AQI) by October 21-22 midnight, and further to ‘moderate’ (184) by Thursday midnight.
The AQI peaked at 500 — the highest measurable value — around midnight at Jadavpur and the Victoria Memorial. Readings exceeded 450 at Rabindra Sarobar, Bidhannagar and Ballygunge, while slightly lower levels were recorded at Fort William (388) and Rabindra Bharati (375). In Ballygunge, the AQI jumped from 32 to 470 on the day of Diwali — a fifteenfold rise.
“Like the rest of the country, Kolkata’s air pollution rose due to uncontrolled bursting of so-called green fireworks rather than weather conditions,” said Gufran Baig, director of SAFAR (System of Air Quality and Weather Forecasting and Research) under the Union Ministry of Earth Sciences. “In fact, the weather this year was better than in previous Diwalis, but we frittered away that advantage with the free-for-all use of these so-called green crackers.”
Baig added that the pollution levels improved quickly only because of favourable weather conditions. “The Diwali sky looked heavy only in certain pockets, especially over urban areas, pointing to the localised impact of fireworks rather than poor atmospheric dispersion. The festival occurring earlier than last year also helped,” he noted.
Scientists from the India Meteorological Department (IMD) agreed. “Our data show that weather conditions in Kolkata remained nearly the same all week, with calm winds and minimum temperatures around 26-27 degrees Celsius (°C),” said Habibur Rahman Biswas, head of IMD Kolkata.
‘Green’ fireworks were permitted following a 2018 Supreme Court ruling, based on claims by government agencies such as the CPCB and the National Environmental Engineering Research Institute (NEERI) that these would reduce emissions by about 30 per cent.
Biswajit Mukherjee, retired chief law officer of the West Bengal Pollution Control Board — who played a key role in curbing fireworks during his tenure — said this was the most polluted Diwali since the 1996 Calcutta high court order.
“I counted at least one blast per second, maybe more, even after the 10 pm deadline was over — not to mention the non-noise fireworks,” said Mukherjee, who lives in Chandannagar, on Kolkata’s north-western fringe.
“We conducted civil society monitoring mainly in hospitals, supposed to be silent areas, and found gross violations,” said Naba Dutta, secretary of Sabuj Mancha. “Most hospitals were bombarded with fireworks, and hardly any visible police action to minimise the noise menace was noted.”
This correspondent observed that even medical students were bursting crackers inside R G Kar Hospital premises.
Sudipta Bhattacharya, a member of the monitoring team, said ambient noise levels reached 80-90 decibels inside hospital compounds, where the limit is 40 decibels.
Every 10-decibel increase doubles the pressure on the ear drums, a noise scientist told this correspondent.
“The concentration of fine particulate matter (PM) 2.5 — the most toxic air pollutant — exceeded 400 micrograms per cubic metre at places like Ramakrishna Mission Hospital, while the national limit is 60 micrograms,” Bhattacharya noted. “The World Health Organization guideline is just 15 micrograms.”
“In areas like Ballygunge, it felt like a war zone with incessant explosions, violations continuing well past midnight, and authorities limiting themselves to ornamental actions like newspaper guidelines, police notices and token arrests,” said a senior citizen from the neighbourhood. “It was like hell had descended upon us, even with all doors and windows bolted.”