Air pollution in Indian cities has traditionally been linked to vehicular emissions, industrial smoke, and particulate matter such as PM2.5 and PM10. However, a new and largely invisible threat has now emerged — inhalable microplastics. A first-of-its-kind scientific study examining airborne microplastics across four Indian cities has revealed that plastic particles smaller than 10 micrometres (µm) are present in urban air, raising fresh concerns about public health and environmental safety.

Microplastics are tiny plastic fragments produced by the degradation of larger plastic items, including packaging materials, synthetic textiles, tyres, and construction waste. While their presence in oceans, rivers, soil, and even food has been widely documented, airborne microplastics have remained an underexplored area of research in India. The new findings suggest that city dwellers may be inhaling plastic particles daily without realising it.

Particles smaller than 10 µm are particularly dangerous because they can penetrate deep into the respiratory tract. Once inhaled, these microplastics can bypass natural filtration mechanisms in the nose and throat and become lodged in the lungs. Scientists warn that prolonged exposure may lead to respiratory inflammation, reduced lung efficiency, and potential long-term health complications. Vulnerable populations such as children, senior citizens, and individuals with asthma or other lung conditions are at an even greater risk.

What makes inhalable microplastics especially concerning is their ability to act as carriers of toxic co-pollutants. Due to their large surface area relative to size, these plastic particles can adsorb hazardous substances present in polluted air, including heavy metals, persistent organic pollutants, and hormone-disrupting chemicals. When inhaled, these contaminants are effectively transported directly into the human body, intensifying their harmful effects.

Urban environments provide ideal conditions for the generation of airborne microplastics. High traffic volumes contribute to tyre wear particles, while synthetic clothing sheds plastic fibres during daily use. Construction activities, road dust, open waste burning, and inadequate plastic waste management further increase the concentration of microplastics in city air. Combined with already severe air pollution levels, inhalable microplastics represent an additional and largely unregulated pollutant.

Despite growing scientific evidence, current air quality monitoring systems in India do not account for airborne microplastics. Existing regulations focus mainly on conventional pollutants such as particulate matter, nitrogen oxides, and sulphur dioxide. Researchers have emphasised the urgent need to include microplastic monitoring in air quality assessments and to implement stricter controls on plastic production, usage, and disposal.

The study highlights a critical gap in environmental policy and public awareness. Unlike visible smog or dust, inhalable microplastics remain invisible to the naked eye, making them easy to ignore. However, their persistence, ability to accumulate in the human body, and interaction with toxic pollutants make them a silent yet serious threat to urban health.

As plastic consumption continues to rise and Indian cities expand rapidly, inhalable microplastics could become a major contributor to environmental and health risks. Addressing this hidden toxin will require coordinated efforts involving scientific research, policy intervention, sustainable alternatives to plastic, and improved waste management systems — before the problem becomes deeply embedded in the air that millions breathe every day.