A groundbreaking study from the Indian Institute of Science Education and Research (IISER), Kolkata has uncovered a disturbing new dimension of urban air pollution: inhalable microplastics. The research, which directly measured air quality at human breathing height, has identified Kolkata and Delhi as the cities with the highest concentrations of this invisible threat.
The Alarming Findings: A Plastic Bottle in Your Lungs
The study, titled 'The Dawn of a New Air Pollutant: Inhalable Microplastics as Emerging Vectors of Hazardous Contaminants and Their Implications for Human Health', was conducted in crowded markets across four major Indian cities. The results, published on November 15, 2025, place Kolkata at the top with an average concentration of 14.23 micrograms of inhalable microplastics (iMPs) per cubic metre of air. Delhi follows closely behind at 14.18 µg/m³.
Researchers have calculated a staggering long-term impact. They estimate that an average resident of Kolkata inhales approximately 2.9 grams of microplastics over a lifetime. To put this into perspective, this is roughly equivalent to breathing in the material of a small plastic bottle over time.
More Than Just Dust: The Hidden Dangers in Every Breath
These inhalable microplastics are tiny particles smaller than 10 micrometers, making them a significant but invisible component of the air we breathe. The study reveals that microplastics now account for up to 5% of PM10 and 2.5 particles in India's metropolitan markets, adding a new layer of danger to already polluted urban air.
The primary sources of these airborne plastics are everyday items found in urban environments. Polyester from textiles, packaging materials, vehicle wear, and footwear are the main contributors. Unlike ordinary dust, microplastics are lightweight and aerodynamic, allowing them to remain suspended in the air for long periods and travel across cities and even countries.
Perhaps the most concerning discovery is that these particles act as "Trojan Horses". Once inhaled, they can penetrate deep into the lungs, enter the bloodstream, and reach vital organs. They carry a cocktail of hazardous substances, including:
- Pathogenic microbes like the fungi Aspergillus fumigatus and Candida, and antibiotic-resistant Bacillus species.
- Toxic chemical additives such as diethylphthalate (DEP), a common plasticizer. Delhi, Kolkata, and Mumbai showed the highest presence of DEP, which is linked to hormonal imbalances, reduced fertility, and developmental disorders.
- Heavy metals like lead, with levels in Kolkata and Delhi exceeding national safety limits. Chronic lead exposure is known to damage the brain, kidneys, and nervous system.
A Call for Action: How to Reduce the Risk
According to lead researcher Professor Gopala Krishna Darbha from the Department of Earth Sciences, the constant movement and friction in crowded markets easily release plastic fibres from clothes and other materials into the air.
The scientists recommend several measures to combat this growing threat:
- Reducing the use of single-use plastics.
- Avoiding synthetic and overly weathered clothing.
- Supporting proper waste segregation.
- Promoting greener urban spaces and vehicle-free market zones.
- Encouraging the use of natural fabrics like khadi (cotton).
This study serves as a critical wake-up call, highlighting that the plastic pollution crisis is not just an environmental issue but a direct and immediate public health emergency. The long-term implications point to increased risks of cancer, lung diseases, gastrointestinal issues, and endocrine disorders, demanding urgent policy and individual action.
