Indian researchers report toxic mercury and microplastics in Delhi’s air, linking emissions mainly to fossil fuels, industry, and vehicles.
BY PC Bureau
Delhi’s worsening pollution crisis has taken a new turn, with Indian researchers reporting dangerous levels of toxic metal mercury in the city’s air.
A first-of-its-kind study by scientists at the Indian Institute of Tropical Meteorology (IITM), Pune, found an average of 6.9 nanograms of mercury per cubic metre in Delhi’s atmosphere—far above the global averages of 1.7 (Northern Hemisphere) and 1.3 (Southern Hemisphere). The findings, based on data collected between 2018 and 2024, were published in the journal Air Quality, Atmosphere & Health.
Researchers said that 72–92% of mercury emissions came from human activities such as fossil fuel burning, industry, and vehicles. Natural sources such as soil re-emission and photochemical processes accounted for only 8–28%.
People in the capital inhale about 10.7 microplastic particles per day in winter and 21.1 per day in summer, according to a new study by the Indian Institute of Tropical Meteorology (IITM), Pune, in collaboration with Savitribai Phule Pune University.
This is the first study to… pic.twitter.com/uHnqPICSWM— The Quint (@TheQuint) September 5, 2025
The World Health Organization lists mercury among the top 10 chemicals of major public health concern. While Delhi’s mercury levels remain below WHO thresholds, experts warned of long-term health risks from chronic exposure. Encouragingly, the study noted that mercury concentrations declined over the years studied.
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Microplastics add to crisis
The mercury findings come alongside another alarming report that detected microplastics in Delhi’s air across PM10, PM2.5, and PM1 categories. Average concentrations were 1.87 particles per cubic metre for PM10, 0.51 for PM2.5, and 0.49 for PM1.
Adults in Delhi inhale nearly twice as many microplastic particles in summer (21.1 per day) compared with winter (10.7 per day), representing a 97% seasonal surge. Constant exposure, the study warned, could fuel rising cases of bronchitis, pneumonia, lung inflammation, and even cancer.
Both studies underline the urgent need for integrated monitoring and stronger pollution-control policies to tackle Delhi’s toxic air.
