In a striking contrast to the Tamil Nadu government’s recent assurance to the National Green Tribunal (NGT) that air pollution in Chennai is within safe limits, a Greenpeace India study has revealed “alarming” levels of nitrogen dioxide (NO₂) pollution throughout the city. Released on Thursday, the report underscores the troubling reality that NO₂ concentrations in 2023 consistently exceeded the World Health Organisation’s (WHO) annual guideline of 10 µg/m³ and India’s National Ambient Air Quality Standards (NAAQS) of 40 µg/m³ at nearly all air quality monitoring stations across Chennai. In fact, the city’s average NO₂ levels were found to be double the WHO’s recommended threshold.
The highest levels of pollution were recorded near Alandur Bus Depot, while Gandhi Nagar in Ennore and Royapuram also registered NO₂ concentrations above the WHO guideline. The findings not only expose the growing air quality crisis in southern cities like Chennai but also highlight the persistence of pollution in urban environments, which often go unnoticed compared to the more widely reported pollution issues in northern India. Greenpeace attributes the alarming levels of NO₂ to the transportation sector, which remains the largest contributor to air pollution in urban centres.
S Kamal, a prominent transportation activist, pointed out the stagnation of Chennai’s bus fleet, which has remained at around 3,300 buses for nearly a decade. This number falls well short of the ideal fleet size of 4,500 buses, as recommended by the Union Ministry of Urban Development. The inadequacy of the public transport system in Chennai is exacerbating pollution levels and contributing to public health concerns. Prolonged exposure to NO₂ has been linked to respiratory issues such as asthma and inflammation, as well as cardiovascular diseases.
From a sustainability standpoint, these findings are a wake-up call for Chennai’s urban planners. The lack of a robust, efficient, and sustainable public transport system is worsening the city’s air quality and hindering efforts to reduce carbon emissions. Addressing this challenge requires a comprehensive overhaul of the transportation system, investing in cleaner, greener technologies, and ensuring that public transport can efficiently cater to the growing population of Chennai. Implementing such changes would significantly improve the city’s air quality and contribute to a more sustainable future for all its residents.
