Microplastics found in air above pristine Sunderbans island, says IISER study

Kolkata: A recent study conducted by the Indian Institute of Science Education and Research (IISER) Kolkata, discovered airborne microplastics drifting above the protected mangrove forests of Sunderbans—the first such evidence recorded in any of India’s natural ecosystems.

The findings, now published in the international journal Science of the Total Environment, reveals that the air above a completely uninhabited island in the heart of the Sunderbans contains tiny plastic particles known as microplastics—invisible to the naked eye yet potentially harmful to plants, animals and humans alike.

The discovery which is both scientific and symbolic is a reminder that the fight against plastic pollution must not only focus on what lies beneath our feet or flows through our rivers, but also on what now floats silently in the sky above us.

The study was led by Gopala Krishna Darbha, and his team which conducted an intensive eight day winter campaign in January 2025 using high-volume air samplers to detect PM10-bound microplastics. From their study they found an average of ten microplastic particles per 100 cubic metres of air, an alarmingly high concentration for such a remote and protected region. “What we are seeing is that the air over the Sunderbans is no longer pure. Plastic particles are travelling through the atmosphere and reaching even the most isolated mangrove forests. The air itself has now become a carrier of pollution,” said Abhinandan Ghosh, the study’s lead author.

In the analysis, fibres and fragments emerged as the dominant types of microplastics, with black coloured particles—typically from discarded single-use plastic bags and degraded fishing nets—being the most common. Using advanced μ-Raman spectroscopy, polymer types such as polypropylene (PP) and polyethylene (PE), materials widely used in packaging, textiles and fishing gear were identified.

The research team was struck by the way wind direction and local meteorology shaped the movement of these plastics. During land-breeze hours, when winds blow from land towards the sea, microplastics from the urban and rural regions of South Bengal, including Kolkata and the buffer zones of the Sunderbans Biosphere Reserve, were carried deep into the forest. During sea breeze periods, the reverse occurred: marine winds brought plastic particles inland, lifted from seawater by bubble bursting and wave action that inject microplastics into the atmosphere. It has been found that foggy conditions led to a sharp rise in microplastic concentration.

“Our findings highlight a silent atmospheric pathway for plastic transport. The atmosphere connects continents and oceans; once microplastics enter this cycle, they can reach anywhere on earth. Protecting ecosystems like the Sunderbans now requires understanding the air above them as much as the water around them,” said Gopala Krisha Darbha at IISER, Kolkata.

According to the researchers, the discovery is alarming because these airborne plastics can settle on mangrove leaves, soils and waterways, threatening the fragile ecology of one of the world’s largest mangrove systems. The researchers at the IISER have urged policymakers to include airborne microplastics within India’s National Clean Air Programme (NCAP) and coastal pollution frameworks. Plastic pollution is no longer limited to land or water—it has become an atmospheric issue.