Every Diwali, the night sky turns into a canvas of colour. Golden fountains of light shoot upwards, flower pots scatter sparkling trails across balconies, and rockets burst into brilliant shades of red, green and blue. For a few hours, the neighbourhood seems to glow with celebration.
But when the last spark fades, another side of the festivities begins to show. A cloud of smoke hangs over the streets, the familiar smell of burnt chemicals lingers in the air, and the sound of crackers gives way to coughing, irritated eyes, and difficulty breathing.
Firecrackers may last only a few seconds, but the pollution they leave behind can stay in the air much longer. This has led to the growing popularity of an alternative: green crackers. But are they actually better for the environment, and does the word ‘green’ mean they are safe to burst?
What happens when a firecracker goes off?
The colourful explosions we enjoy are the result of carefully mixed chemicals that release energy when ignited. But this reaction also releases a cocktail of pollutants into the atmosphere.
Conventional firecrackers can emit particulate matter (PM2.5 and PM10), sulphur dioxide, nitrogen oxides and other harmful gases. These tiny particles can enter the respiratory system, with some travelling deep into the lungs and even entering the bloodstream.
For people with asthma, respiratory conditions or heart problems, exposure can make existing symptoms worse. Children and older adults are particularly vulnerable. Even otherwise healthy people may experience coughing, throat irritation, breathlessness and burning eyes.
Green crackers use modified chemical formulations designed to reduce particulate emissions compared with conventional fireworks. Photograph: (Khan Global studies)
There is also the problem of noise pollution. The sudden, loud bursts can cause distress to infants, older people, pets and those sensitive to sound.
And when thousands of crackers are burst across a city within a few hours, their emissions add to the pollution already coming from vehicles, industries and other sources.
What makes a firecracker green?
To address this problem, scientists at the Council of Scientific and Industrial Research (CSIR), along with the National Environmental Engineering Research Institute (NEERI), developed what are known as green crackers.
Introduced in India in 2019, these are firecrackers made with modified chemical formulations and reduced quantities of certain raw materials. The idea is simple: retain the familiar sparkle and sound of fireworks while releasing fewer pollutants.
Developed by CSIR and NEERI, green crackers fall into three categories: SWAS, STAR and SAFAL, each using a different approach to reduce emissions.
Photograph: (GCESCJ)
According to NEERI’s criteria, a green cracker must reduce particulate matter emissions by at least 30% compared with its conventional counterpart. Another qualifying formulation must achieve at least 20% lower particulate emissions, along with a minimum 10% reduction in gaseous emissions such as sulphur dioxide and nitrogen dioxide.
The chemistry behind the sparkle
So, what actually changes inside these crackers?
Scientists work on changing the ingredients, reducing the amount of material used, and making combustion more efficient.
There are three recognised categories:
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SWAS (Safe Water Releaser): These crackers release water vapour during combustion, which helps suppress dust particles and reduce particulate emissions.
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STAR (Safe Thermite Cracker): These use iron oxide-based formulations to improve combustion efficiency and reduce emissions.
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SAFAL (Safe Minimal Aluminium): These use zeolite-based materials, which have a porous structure, to help reduce the amount of aluminium required.
Green crackers also exclude certain harmful chemicals, including barium nitrate, and use modified formulations to reduce ash and other emissions.
Are green crackers completely safe?
Here’s where the distinction matters: less polluting does not mean pollution-free.
Even green crackers release particulate matter and gases when burnt. Some green crackers could release higher numbers of ultrafine particles than conventional ones. These extremely tiny particles are concerning because they can penetrate deep into the respiratory system.
This does not mean every green cracker is more harmful, but it shows why simply measuring the total quantity of emissions does not tell the whole story.
There is another important point. A 30% reduction in emissions from an individual cracker does not mean the air in a city becomes 30% cleaner. The overall impact depends on how many crackers are burst, the pollutants they release, weather conditions, and other sources of pollution.
Green crackers, therefore, are a step towards reducing the damage, not a licence to burst as many as we like.
Choosing fewer firecrackers and exploring alternative ways to celebrate can help reduce Diwali’s impact on the air we breathe. Photograph: (The Indian Express)
If buying them, look for products from authorised manufacturers with valid certification rather than trusting packaging that simply says ‘eco-friendly’ or ‘pollution-free’.
Perhaps the best way to make Diwali brighter is to think beyond the few seconds a firecracker lights up the sky. Green crackers offer a way to reduce some of the harm, but they cannot take pollution out of the picture entirely.
Choosing to burst fewer crackers, exploring other ways to celebrate, and being mindful of the air we all share can make a difference. After all, a festival of lights should leave behind happy memories, not air that makes it harder for people to breathe.
