The world’s two most populous nations are racing to grow richer. But one appears to be further along in learning how to grow without choking on its own pollution.
A major new study published in Nature Cities has mapped, for the first time at a global scale, whether cities are managing to grow economically without increasing their dependence on fossil fuels.
The findings place India among the countries where urban growth remains tightly tied to rising pollution, even as China, Europe and parts of North America show signs of cleaner economic expansion.
Researchers analysed 5,435 cities with populations above one lakh between 2019 and 2024 using satellite observations of nitrogen dioxide (NO2), a pollutant strongly associated with fossil fuel combustion from transport, industries and thermal power generation. The data was paired with city-level GDP estimates to classify urban centres into four categories: “cleaner and richer”, “dirtier and richer”, “cleaner and poorer”, and “dirtier and poorer”.
Globally, around 80% of cities with significant trends fell into the “cleaner and richer” category, where economies expanded while NO2 pollution declined. Major metropolitan regions across East Asia, Western Europe and North America showed varying degrees of success in decoupling economic growth from fossil fuel-linked pollution.
India, however, stood out for a different reason. Of the 902 Indian cities examined in the study, 15.3% showed a statistically significant increase in NO2 levels between 2019 and 2024. Researchers said this signals that economic activity in many Indian urban centres is becoming more fossil fuel-intensive rather than less.
India also dominated the study’s “dirtier and richer” category, described by researchers as cities where GDP per capita rises alongside increasing pollution. Of the 390 cities worldwide in this category, 35.4% were in India, the highest share for any country.
“These are not failing cities. They are growing cities,” the study noted, pointing to automobile-dependent transport, heavy industry, urban sprawl and fossil fuel-based electricity generation as key drivers behind the trend.
Among the prominent Indian cities highlighted in the study’s top ten “dirtier and richer” group was Nashik. India also appeared in the study’s smallest but most worrying category — “dirtier and poorer” cities — where pollution rises even as local economies stagnate or weaken.
At the same time, some Indian metros showed a more encouraging trajectory. Delhi, Mumbai and Kolkata are among the large Indian cities placed in the study’s “cleaner and richer” group, suggesting that economic growth and falling NO2 levels can coexist under certain conditions.
China Contrast Striking
China accounted for 719 “cleaner and richer” cities, the highest number globally. Major urban centres such as Beijing, Shanghai, Guangzhou and Chengdu recorded declining NO2 levels alongside rising incomes. Researchers linked this to large-scale air quality interventions, including stricter industrial emission controls, relocation of polluting industries and rapid electrification of public transport systems.
India, by comparison, contributed only 119 cities to the “cleaner and richer” category. The study relied on observations from the Sentinel-5P satellite’s TROPOMI instrument, which tracks atmospheric NO2 concentrations at high spatial resolution. Scientists adjusted the data for weather conditions such as rainfall, wind and temperature to isolate changes mainly linked to human activity.
Researchers stressed that falling NO2 levels do not automatically mean cities have become climate friendly or fully sustainable. The findings instead indicate whether economies are reducing their dependence on fossil fuel-intensive activity or shifting towards cleaner combustion technologies.
The paper said governance quality, environmental regulation and technology adoption play a major role in determining whether cities become cleaner as they grow richer.
It also warned that rapidly urbanising regions such as South Asia and the Middle East risk locking themselves into pollution-intensive development pathways unless governments invest heavily in cleaner energy systems, sustainable public transport and stricter urban emission controls.
