Diwali in Delhi: What are green crackers and why India’s Supreme Court allowed them

Dubai: As India’s Supreme Court eased the blanket ban on firecrackers for Diwali, “green crackers” have once again ignited debate. The court has allowed limited use of these supposedly less-polluting fireworks in Delhi-NCR between October 18 and 21, under strict time and safety limits.

So, what exactly are green crackers — and are they truly better for the environment?

“Green crackers” are a cleaner alternative to traditional fireworks, developed by the Council of Scientific and Industrial Research (CSIR) and the National Environmental Engineering Research Institute (NEERI).
They are designed to emit 20–30 per cent less particulate matter (PM2.5 and PM10), and lower sulphur and nitrogen oxides, two major contributors to Delhi’s winter smog.

Instead of harmful chemicals such as barium nitrate and aluminium, these fireworks use reduced metal content, dust suppressants, and stabilisers that limit smoke and noise.

CSIR-NEERI has developed several categories of green crackers, including:

SWAS (Safe Water Releaser) – suppresses dust and emits water vapour during explosions.

STAR (Safe Thermite Cracker) – uses reduced potassium nitrate and sulphur.

SAFAL (Safe Minimal Aluminium Firework) – cuts metallic emissions.

Traditional fireworks rely heavily on barium nitrate, aluminium, sulphur, and potassium chlorate, producing dense smoke, toxic metals, and greenhouse gases when ignited.

These chemicals give Diwali fireworks their bright colours and thunderous sound but also generate high PM2.5 concentrations, carbon monoxide, and metallic residues that linger in the air.

Green crackers, by contrast, use alternative oxidisers and binding agents that reduce particulate emissions by roughly 20–30 per cent and lower noise levels by up to 125 decibels. They also leave behind less ash and debris, easing post-celebration cleanup.
However, experts caution that the improvement is relative, not absolute — even “green” versions still release harmful ultrafine particles when used extensively.

The Supreme Court and pollution-control authorities have stressed that only certified green crackers can be sold. To verify authenticity:

Each approved product must carry a green CSIR-NEERI logo.

A QR code printed on the package lists its chemical composition and emission data.

The QR code can be scanned using the NEERI app to confirm compliance.

Online sales are banned, and only licensed outlets may stock them.

Crackers manufactured outside Delhi-NCR cannot be sold in the region.

Patrolling teams will seize unverified or smuggled products, and licences of violators will be suspended.

The court said it was taking a “balanced approach”, recognising cultural traditions while enforcing environmental safeguards.
Chief Justice B.R. Gavai noted that a total ban had encouraged black-market trade and inflow of more toxic, unregulated fireworks into the capital.

“Crackers are being smuggled into Delhi-NCR and they cause more damage than green firecrackers,” Justice Gavai observed.

The ruling allows certified green crackers to be used from 6 p.m. to 10 p.m. during the four-day Diwali window, under supervision of pollution-control authorities. Only NEERI- and PESO-approved manufacturers may produce them.

Scientists agree the new compositions are an improvement but not a complete solution.
Studies by Delhi Technological University found that even green crackers emit ultrafine particles capable of penetrating deep into the lungs.

Environmental activist Bhavreen Kandhari said the reductions achieved in lab tests “become meaningless in Delhi’s winter air, where pollutants linger for days.”

Still, regulators see the move as a practical compromise between faith and public health. Traders hope certification and QR codes will curb illegal sales and promote cleaner options.

As Diwali nears, Delhi once again faces its annual challenge: keeping the festival bright — without darkening its skies.