After microplastics, Delhi’s air contaminated by mercury, study warns
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A new study by Indian researchers has raised alarms about Delhi’s worsening air pollution, now linked not only to microplastics but also to mercury, a highly toxic metal.
The research found that the capital’s air contained an average of 6.9 nanograms of mercury per cubic metre — far exceeding the global averages of 1.7 nanograms per cubic metre in the Northern Hemisphere and 1.3 in the Southern Hemisphere.
The study, led by scientists from the Indian Institute of Tropical Meteorology (IITM) in Pune, is the first of its kind in India. It was published in the journal Air Quality, Atmosphere & Health by Springer and examined data from 2018 to 2024 on gaseous elemental mercury (GEM), a major atmospheric pollutant.
According to the study, between 72 and 92 per cent of mercury emissions in Delhi stem from human activities. These include fossil fuel combustion, industrial processes, and vehicular emissions. “Natural contributions (8 to 28 per cent) were attributed to re-emission from soil and photochemical processes,” the researchers noted.
The World Health Organization (WHO) classifies mercury as one of the top 10 chemicals of major public health concern.
While chronic exposure levels in Delhi were higher than usual, the amounts recorded were still below WHO thresholds.
The researchers stressed, “This study highlights the spatial variability, source pathways, and potential health implications of urban mercury pollution in Indian cities and underscores the need for integrated monitoring and policy interventions.”
The study also offered a small piece of good news: mercury levels have decreased over the years compared to earlier measurements.
This study follows another alarming report that found high levels of microplastics in Delhi’s air across PM10, PM2.5, and PM1 categories. The average concentrations were 1.87 microplastics per cubic metre for PM10, 0.51 for PM2.5, and 0.49 for PM1.
The report highlighted that adults inhale nearly twice as many microplastic particles in summer compared to winter. The daily average rose from 10.7 particles in colder months to 21.1 during hotter seasons, marking a 97 per cent increase.
Although there is no established safe limit for microplastic inhalation, constant exposure may lead to serious health issues such as bronchitis, pneumonia, lung inflammation, and even cancer.
Delhi’s air pollution crisis, now compounded by mercury and microplastics, underlines the urgent need for comprehensive environmental monitoring and stricter pollution control policies.
