Mumbai needs a regional airshed approach to combat pollution: Study

Mumbai: 2024: While Mumbai has focused on controlling local sources of air pollution, a new pan-India study suggests this approach alone may not be enough to improve the city’s air quality, especially during the winter months when pollution spikes due to both internal and external factors.

The study proposes that Mumbai be integrated into a coastal airshed which includes all its satellite cities to effectively address and manage, urban and non-urban (outside the city administrative region) emission sources. In this process, the regional airshed will foster cooperation among the Urban Local Bodies, which are influencing each other’s air quality.

The peer-reviewed study, Designating Airsheds in India for Urban and Regional Air Quality Management, published in MDPI’s Air journal, recommends dividing India into 15 regional airsheds, each tailored to the specific climatic and pollution patterns of its region.

This approach, the study indicates, could significantly improve Mumbai’s air quality by tackling pollution from both inside and outside the city.

An airshed is a geographic area where air pollution is measured and managed as a whole. 

It recognises that air pollution doesn’t stop at city or state borders—pollutants can travel across regions. As a result, effective pollution management requires cooperation between cities, states, and even neighbouring countries.

Mumbai’s air quality worsens significantly during the winter months, driven by a combination of meteorological factors and pollution sources from both within and beyond the city limits. 

According to the World Air Quality Report 2023, Mumbai’s PM2.5 levels rose by 23 per cent in January 2023 compared to the same period in 2022, making it one of the worst-affected cities globally during the winter season.

Sarath Guttikunda, lead author of the study and founder of UrbanEmissions.info, stated: “Mumbai is a significant regional contributor to air pollution. While the city can gain considerable benefits from managing pollution within its immediate surroundings, this relationship is reciprocal; the surrounding satellite cities also stand to benefit greatly from efforts to control emissions originating in Mumbai. Coordinated management across Mumbai and its neighboring areas could create a positive feedback loop, enhancing air quality and health outcomes for the entire Western airshed,” he added.

The study proposes dividing India into 15 regional airsheds, each tailored to address the distinct climatic and pollution patterns of that region. 

These airsheds include: Himalayas (2 airsheds), Gangetic Plains (4 airsheds), Plateaus (4 airsheds), Arid/Desert (1 airshed), Coastal Plains (3 airsheds) and Islands (1 airshed).

“While regions like the IGP bear the brunt of industrial and agricultural pollution, contrary to popular belief, coastal cities like Mumbai have also witnessed a spike in pollution levels, particularly in winter, despite the benefits of land-sea breezes.In an urban regional airshed, the participating members would include a broad institutional setup, involving urban local bodies (ULBs), state officials, ministries, and regional stakeholders. This larger collaboration is essential to addressing shared air quality issues in coastal cities like Mumbai,” Guttikunda said.