Have ‘green’ crackers brought down pollution? | Explained

The story so far: Ahead of Deepavali, the Supreme Court legalized the sale of “green” crackers in a bid to balance three conflicting interests: people’s “emotions” during the festive season; pollution from burning fireworks; and livelihood concerns of those working in the fireworks industry. The largely small-scale informal sector has been affected by the cracker ban in the National Capital Region since 2018.

How to make ‘green’ crackers?

In 2018, Nagpur-based CSIR-National Environment and Engineering Research Institute (NEERI) initiated the development of ‘green’ crackers, which are reported to reduce particle emissions by a minimum of 30% and sometimes up to 80% while maintaining brightness, safety and shelf life. This was largely achieved through three major chemical formulation changes: the use of additives such as ‘zeolite’; water-releasing molecules such as boron-based reagents to act as dust suppressants; and the addition of metallic composites to increase the combustion temperature and improve combustion efficiency. Traditionally, fireworks were made of barium nitrate, antimony and a host of metals that have been linked over the years to respiratory diseases and even cancer.

One of the most popular fireworks, the ‘pot’ in its green avatar features a mixture of water and lime chemically stored in the cracker. When the light turns on, the light also triggers water, and its makers claim that the moisture soaks dust and smoke particles, allowing them to settle instead of dispersing into the air. NEERI claims that tests conducted in its laboratories have shown a reduction of about 30% in particulate matter and also that nitrous oxide emissions as well as sulfur dioxide emissions are reduced when these pots are burned. Green sparklers use 32% potassium nitrate, 40% aluminum powder, 11% aluminum shavings and 17% “proprietary additives” to reduce PM10 and PM2.5 to 30%.

Similarly, a new ‘bombshell’ formulation called ‘SWAS’ uses 72% ‘proprietary additive’, 16% potassium nitrate oxidizer, 9% aluminum powder and 3% sulfur to reduce PM10 and PM2.5. Since these crackers were developed, demonstrations have been conducted by NEERI at major fireworks manufacturing units such as Sivakasi in Tamil Nadu.

In what direction were the purchases made?

According to the Commission for Air Quality Management (Delhi-NCR), NEERI had also developed a Standard Operating Procedure (SOP) to register green cracker manufacturers and ensure technology transfer of formulations for the production of such crackers. The list of green crackers for registration and grant of individual products has been put on NEERI’s website. It will require the manufacturer to obtain multiple registrations from NEERI depending on the number of products. Only manufacturers who have an explosives license from the Petroleum and Explosives Safety Organization (PESO) will be granted registration by NEERI. This year, there were around 1,500 applications for licenses to produce these crackers; the vast majority of them were from Tamil Nadu followed by West Bengal. The term “green” crackers is actually a misnomer, as green often refers to products with zero emissions or smoke. For example, an electric vehicle is ‘green’ because it is powered by a battery that has no carbon emissions. In a 2023 academic paper, scientists from NEERI coined the more accurate term ‘Reduced Emission Fireworks’ while evaluating the results from such crackers. But the SC order calls these products “green.”

Are green crackers less polluting?

The manufacturers’ claim is that they reduce particulate matter pollution by 30%. However, these are numbers calculated by the laboratory itself and have not been verified in real-world conditions. In its decision, the Supreme Court noted that there was “not much improvement” in overall air quality compared to 2018 and 2024. But he used it to conclude that allowing green crackers for Deepavali, despite restricting their use, would not make the deteriorating air quality much worse than it already was. Air quality dropped to “very poor” on October 20 and 21, according to readings from sensors via NCR. Air quality was already declining in the days leading up to the festival. This is not unusual in mid-October, given the dropping temperatures and drop in wind speed. Several sensors recorded particulate matter concentrations well above 1,000 micrograms per cubic meter. Stubble burning in Punjab has also been a contributor, but no official or independent scientific measurement of their relative contribution is yet available.