Since late 2023, firecracker manufacturing units in Bengal producing “green crackers” were only required to inform the state pollution control board (PCB) before beginning production, with no inspections conducted by the board — a move that environment activists and PCB sources said created a significant loophole in regulation.

The lack of oversight, they allege, allowed manufacturers to bypass guidelines, leading to indiscriminate bursting of crackers this Diwali and a subsequent drop in air quality.

According to environmental groups, the root of the problem lies in the state PCB’s decision to classify green cracker units under the “white category”, which is reserved for non-polluting industries. They said this classification effectively ensured two years of zero monitoring of ingredients used, production volumes, or compliance with approved formulations.

“The state PCB put green cracker manufacturing units in the white category. This ensured there was zero monitoring. What ingredients were used? Whether the units followed the NEERI-approved green cracker formulations is completely unknown to the board,” said Biswajit Mukherjee, president of Paribesh Academy, an environmental organisation.

The National Environmental Engineering Research Institute (NEERI) provides the formulations for green crackers. An official from NEERI said that it is the responsibility of enforcement agencies to ensure that manufacturers follow the prescribed formulations.

“The post-Diwali air pollution and rampant noise violations are direct outcomes of the PCB’s dilution of rules,” said Mukherjee of Paribesh Academy, who has also filed a petition with the National Green Tribunal (NGT) against the board’s decision to classify green cracker units as non-polluting white-category industries.

Adding to the concern, a PCB official admitted that under the white category, manufacturers only needed to submit a self-declaration to start production. “There was no inspection by the PCB,” the official said.

Noise limit relaxed too

The state PCB in 2023 also relaxed the permissible noise limit for firecrackers — from 90 decibels to 125 decibels, measured at a distance of 4 metres from the point of bursting. Activists said this has further contributed to violations of noise norms during festive seasons.

Category clash

The classification of industries in India is managed by the Central Pollution Control Board (CPCB), based on a pollution index that takes into account the potential to pollute air and water and the hazardous waste generated. The categories — in descending order of pollution potential — are red, orange, green, white, and blue.

When the CPCB released its industrial categorisation list in 2016, firecracker units were placed under the red category, said a CPCB official. “There was nothing called green crackers back then,” the official said.

The concept of green crackers was introduced a few years later, leaving the responsibility of categorising such units to the state PCBs. “Our guidelines state that if a unit falls outside any existing category, the state PCB must classifyit accordingly,” the CPCBofficial added.

Earlier this year, the CPCB released a revised classification list, placing green cracker manufacturing units under the orange category. In February, the CPCB sent a letter to all state PCBs, directing them to follow the new classification. However, Bengal’s PCB continued to list these units under the white category, environment activists alleged.

Delayed update

A state PCB official told Metro on Wednesday that theBengal board updated theclassification in September 2025, moving green cracker units from white to orangecategory.

“Existing units will now need a consent to operate, while new units must obtain consent to establish before setting up factories,” a PCB official said.

“Hardly any unit has sought permission since September,” the official added.