Chennai Air Quality Woes; Alandur Bus Depot reported the highest level of NO2 concentration- Greenpeace Report
Chennai, India –December 4, 2024: A latest report by Greenpeace India, "Beyond North India: NO₂ Pollution and Health Risks in Seven Major Indian Cities", reveals alarming levels of nitrogen dioxide (NO₂) pollution in Chennai
Nitrogen dioxide (NO₂) is a near-invisible toxic gas closely linked to traffic and fuel burning, common in urban areas. That means vehicles and energy generation from fossil fuel are important sources of NO₂.
The WHO recommends an annual NO2 concentration of no more than 10 µg/m³, while the NAAQS standard is 40 µg/m³. In 2023, the city's annual average NO2 was twice the WHO guideline, exceeding the limit at all but one Continuous Ambient Air Quality Monitoring station (CAAQM). The highest average was recorded at Alandur Bus Depot in southern Chennai, near busy roads and an airport. Two stations, Gandhi Nagar Ennore and Royapuram, located within 10 meters of major roads, also surpassed the WHO guideline. Road traffic is a major source of NO2 pollution.
Annual average NO2 concentrations for all CAAQM monitors in Chennai, 2023. Monitoring stations we classified as roadside are shown in dark blue.
Overwhelming scientific evidence links NO₂ exposure to adverse health impacts such as risk of asthma, airway inflammation, respiratory irritation, and the worsening of existing respiratory conditions. It can impair lung development, intensify allergies and increase susceptibility to respiratory mortality and death from circulatory diseases, ischemic heart disease, and even lung cancer. Ten percent of the total population in Chennai consists of children under six, who are particularly vulnerable to NO2 health effects. Importantly, these effects impact all children aged 0-18. Recent research suggests that NO2 pollution in Chennai in 2015 may have contributed to up to 1,420 cases of pediatric asthma (Achakulwisut et al. 2019).
“This report underscores a crucial truth: air pollution is not limited to Delhi or North India. The transportation sector is the largest contributor to high NO₂ levels across cities in India. As cities grow, the rise in private vehicles worsens air quality and jeopardizes public health. To tackle this, we need a fundamental shift towards a sustainable, efficient public transportation system. Investing in cleaner, more accessible transit options is not just an environmental necessity—it’s an urgent public health imperative. The government must prioritize cleaner mobility solutions to ensure a healthier future, said Selomi Garniak, Climate Justice Campaigner at Greenpeace India.
India's response to the air pollution crisis, particularly NO2 pollution, falls woefully short of global health standards. The country’s (NAAQS) are far less stringent than WHO guidelines. Despite significant advancements in understanding the health risks posed by air pollution, especially at low exposure levels, India has not updated its NAAQS since 15 years . This outdated regulatory framework fails to protect public health adequately, leaving millions vulnerable to the severe consequences of air pollution.
Air pollution is a growing public health threat in India, requiring bold, innovative solutions. One such solution is an affordable 'Clean Air Concession' for public transportation. By making mass transit more accessible, this policy can encourage people to leave their cars behind, reducing congestion and harmful emissions. This simple measure can significantly improve air quality, public health, and create more inclusive, healthier cities. said Aakiz Farooq, Mobility Campaigner at Greenpeace India.
Poor air quality in major Indian cities is a serious public health concern. To address this, Greenpeace India recommends a region-specific approach for cities like Bengaluru, Hyderabad, Chennai, Mumbai, Kolkata, and Pune. In addition to revising NAAQS, the focus should be on strengthening healthcare services to diagnose air pollution-related conditions and implementing a comprehensive health advisory system with public education and timely alerts during high pollution periods. Vulnerable groups, including children, the elderly, pregnant women, outdoor workers, and those with pre-existing conditions, should receive prioritized health interventions.
Local governments should focus on reducing vehicular emissions by enhancing public transport, including fare-free schemes for women. Increased investment is needed in hybrid air quality monitoring networks that combine low-cost sensors, existing systems, and satellite data. This data-driven approach will help track progress and guide effective interventions to reduce pollution levels.
Key Highlights–
Alandur Bus Depot measured the highest level of NO2 concentration higher than guideline over 86% of the year.
Ten percent of total Chennai population consists of children under 6 who are particularly vulnerable to NO2 health effects with 1,420 cases of paediatric asthma in Chennai attributed to NO2 pollution in 2015.
The 5 year trend in NO2 concentration recorded by CAAQM monitors is increasing with six out of eight stations showing a worsening trend.
Road transport is the third largest source of emissions in Chennai accounting for 9% emissions in the EDGAR emission inventory.
Apart from the revisions in NAAQS there should be focus on strengthening primary healthcare services ability to diagnose air pollution related conditions.
Annexure 2-
About Greenpeace
Greenpeace India is a part of the global environmental organisation, dedicated to tackling pressing environmental challenges through advocacy, campaigns, and public engagement. Greenpeace India's Climate Justice Campaign advocates for accountability, equitable policy changes, and climate finance to address the rising climate impacts felt by communities in South Asia.
