Chennai has shown only a modest improvement in air quality despite being part of the National Clean Air Programme (NCAP) since its launch in 2019. According to data shared by the Ministry of Environment, Forest and Climate Change in the Lok Sabha, PM10 levels in the city dropped by just 12.1 per cent in 2024–25 compared to 2017–18.

This is significantly lower than the progress seen in cities like Mumbai (44 per cent), Kolkata (37 per cent), and Delhi (15.8 per cent). Chennai’s annual PM10 average reduced from 66 µg/m³ in 2017–18 to 58 µg/m³ in 2024–25—just under the National Ambient Air Quality Standards (NAAQS) threshold of 60 µg/m³.

However, experts say this improvement is far from adequate given the pace of urban growth, traffic density, and construction activity in the city. “The numbers may look acceptable on paper, but the health impact remains significant,” said a senior pulmonologist at the Government General Hospital.

Under NCAP, Chennai drafted a Clean Air Action Plan targeting pollution sources such as vehicular emissions, dust from roads and construction, and industrial pollutants. Although measures like dust control and bans on open waste burning were included, enforcement remains inconsistent.

Tamil Nadu received Rs 6.52 billion between 2019–20 and 2025–26 through NCAP and 15th Finance Commission grants. Of this, Rs 5.37 billion—around 82.4 per cent—has been utilised. This contrasts with Delhi, which spent only Rs 139.4 million of its Rs 620 million allocation.

Chennai’s performance also appears weak compared to other Indian cities. Thoothukudi, also in Tamil Nadu, cut PM10 levels by 54.5 per cent, while cities like Bareilly (76.8 per cent), Varanasi (74.3 per cent), and Firozabad (59.5 per cent) led the rankings.

Nationally, 103 out of 130 cities under NCAP recorded PM10 reductions. However, many still exceed safe limits, and officials noted that health outcomes cannot be directly attributed to air pollution due to varying socio-economic and biological factors.

As the Centre now targets reducing Air Quality Index (AQI) levels below 50 over the next five years, experts warn that cities like Chennai must urgently scale up interventions. “From electric buses to paving roads and enforcing emission norms, stronger local action is essential,” said Dr S Vishvaja, a doctor-turned-environmental activist.