A recent study published in Nature Cities has shed light on the environmental challenges faced by rapidly urbanizing Indian cities. The research, which analyzed 5,435 cities worldwide between 2019 and 2024 using satellite-based nitrogen dioxide (NO2) data and GDP estimates, found that India has a disproportionately high number of cities where economic growth is accompanied by increasing pollution.
India Dominates 'Dirtier and Richer' Category
Of the 390 cities globally classified as 'dirtier and richer'—where GDP per capita rises alongside pollution—138, or nearly 35.4%, are in India. This is the highest share for any country. The study notes that while major metros like Delhi, Mumbai, and Kolkata have shown cleaner growth trends, many other Indian urban centers continue to rely heavily on fossil fuel-intensive transport, industries, and electricity generation.
Key Drivers of Pollution
Researchers used satellite observations of NO2, a pollutant linked to fossil fuel combustion from transport, industries, and thermal power plants. They categorized cities into four groups: 'cleaner and richer', 'dirtier and richer', 'cleaner and poorer', and 'dirtier and poorer'. Globally, about 80% of cities with significant trends fell into the 'cleaner and richer' category, where economies expanded while NO2 pollution declined. However, India's performance stands in stark contrast.
Among the 902 Indian cities examined, 15.3% showed a statistically significant increase in NO2 levels between 2019 and 2024. The study highlights Nashik as one of the top ten 'dirtier and richer' cities. India also appears in the 'dirtier and poorer' category, where pollution rises despite economic stagnation.
Global Comparisons
China leads the 'cleaner and richer' category with 719 cities, including Beijing, Shanghai, Guangzhou, and Chengdu, which have seen declining NO2 levels alongside rising incomes. Researchers attribute this to large-scale air quality interventions, stricter industrial emission controls, relocation of polluting industries, and rapid electrification of public transport. The study emphasizes that governance quality, environmental regulation, and technology adoption are critical in determining whether cities become cleaner as they grow richer.
Major urban regions in East Asia, Western Europe, and North America have shown varying degrees of success in decoupling economic growth from fossil fuel-linked pollution. In contrast, Indian cities are described as 'growing cities' that are not failing but are heavily dependent on automobile-dependent transport, heavy industry, urban sprawl, and fossil fuel-based electricity.
Implications for Urban Policy
The findings underscore the urgent need for Indian cities to adopt sustainable urban planning and clean energy transitions. Without significant policy interventions, the trend of 'dirtier and richer' growth could exacerbate health and environmental challenges. The study serves as a wake-up call for policymakers to prioritize green infrastructure and stringent pollution controls.
