Does urbanization increase or decrease population health?

When does urbanization actually improve health?

Urbanization can improve health when it comes with strong environmental policies. A 2025 study of Chinese cities found that low-carbon city pilot policies reduced resident mortality rates by cutting carbon emissions and air pollution [1]. The health benefits were largest for urban residents with the poorest health to begin with, suggesting that well-designed policies can narrow health gaps [1].

However, this positive effect is not automatic. The same study showed that the health gains came from restraining urbanization itself and stimulating green innovation—not from urban growth alone [1]. In other words, urbanization only helps health when it is actively managed to reduce pollution and support green technology.

Why does urbanization usually harm health?

In most real-world settings, urbanization tends to worsen health outcomes, especially for chronic diseases and pollution-related illnesses. A scoping review of 102 studies found that sexually transmitted infections, HIV, and dengue occur more frequently in larger cities, while non-communicable diseases show mixed patterns depending on the specific disease and context [5]. Homicides are more common in larger cities, while suicides are more common in smaller ones [5].

The harms are especially clear for vulnerable groups. Rural-urban migrants to metropolitan cities in India had higher odds of pollution-related major illnesses compared to those moving to smaller urban areas [7]. Similarly, rural-dwelling bisexual women in the US faced the largest health disparities, including higher rates of asthma, heart disease, and sexually transmitted infections [4]. Urban gay men, despite having better insurance coverage, still experienced worse health outcomes across several disease domains, suggesting they may not be using healthcare services effectively [4].

Even the physical environment of cities can be toxic. In Jakarta, urbanization had a direct negative effect on quality of life, driven by poor air quality and inadequate transport infrastructure [9]. In Russian cities, soil pollution with heavy metals created an unacceptable total carcinogenic risk for adults in one city and on nearly half the territory of another [8].

What explains the gap between the best-case and typical-case evidence?

The gap comes down to policy, infrastructure, and who you are. The best-case evidence comes from cities that actively implemented low-carbon policies and green innovation [1]. The typical-case evidence comes from cities where urbanization outpaced infrastructure—leading to pollution, poor food environments, and health inequities [7][9][10].

Even within the same country, the effects differ. In China, urbanization reduced mortality in northern provinces but had no effect in southern ones, likely due to differences in geography, history, and health policies [6]. In the US, rural areas had higher mortality than urban areas (4.50% vs. 3.95%), but this was driven by sociodemographic disadvantage, not by worse healthcare quality [2]. This means urbanization can help or hurt depending on whether it reduces or concentrates poverty.

Vacant urban land also shows this split: in shrinking cities like St. Louis, vacant lots were linked to worse health, while in growing cities like Los Angeles, some vacant lots functioned as green spaces that could even reduce non-communicable diseases [3]. The same physical feature—vacant land—can be a health hazard or a health asset depending on how it is managed.

About These Sources

This answer is built on 10 peer-reviewed studies — published from 2021 to 2025, 1 from 2024 or later, 7 in Q1 journals, collectively cited 147 times — selected as the most relevant from 12 studies that passed quality screening, drawn from 66 papers retrieved from a database of over 500 million.

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