Why cities are not as harmful as you think

 After the outbreak of the new crown pneumonia crisis, New York State experienced its first lockdown. Governor Andrew Cuomo tweeted: “New York’s population density is disastrous. It must stop growing, and it must stop now. New York City must Immediately formulate a plan to reduce population density."

Concerns about urban population density and calls to reduce urban population density have always been there. There are reports that the city is empty-in order to avoid the new crown virus, large numbers of people have left high-density urban centers to the suburbs and rural towns. A May survey by the International Council of Shopping Centers found that 27% of adults in the United States are considering moving due to the new crown crisis. More importantly, the survey found that 43% of millionors are considering changing jobs.

However, despite all the claims that the pandemic proves that urban population density is not good, recent studies have put forward the opposite view. Data collected by the World Bank from 284 Chinese cities found that the impact of urban density in the fight against the virus may not be as great as we thought. In fact, cities with very high population densities, such as Shanghai, Beijing, and Shenzhen, have far fewer confirmed cases per 10,000 people than cities with lower population densities.

Similarly, a study found that there is no correlation between population density (in terms of population per square kilometer) in 36 world cities and COVID-19 cases or mortality. A study of 913 major cities and counties in the United States found that there was no significant correlation between population density and the high infection rate of new coronary pneumonia. This may be more about behavior than about available space.

Shima Hamidi, an assistant professor of American health at Johns Hopkins University, said: "We have found that people in densely populated areas are more cautious about this threat and are likely to adopt better protection measures." Her research shows that residents of densely populated areas tend to be more cautious, better maintain social distancing, avoid crowded places, and stay at home. In many densely populated metropolises such as Singapore, Hong Kong, Tokyo and Seoul, the relatively low infection rate seems to confirm this. Although other variables are involved, such as the high rate of mask wearing in Asian countries and the relatively large impact of the coronavirus on a small minority of ethnic groups, this study seems to support the hypothesis that population density has nothing to do with infection rates.

"Population density doesn't matter, what really matters is how to manage density," said Sameh Wahba, director of the World Bank's Bureau of Urban, Disaster Risk Management, Resilience and Land Global Practice.

Waba cited the examples of Manhattan and Mumbai, which have the same population density. However, the floor area of ​​Manhattan is four times that of Mumbai, so in the same area of ​​land, Mumbai has one building and Manhattan has four floors.

"In Mumbai, they only have a quarter of Manhattan for everyone to self-isolate," Waba said. “This makes the people of Mumbai live in a more crowded environment. Although their population density is the same, the effect is very different because of the low building density and the inability to suppress the spread of disease.”