Why do some cities become unsafe after sunset?

Free movement and a mix of uses, buildings that combine commercial, entertainment, occupational, and residential purposes, make a neighbourhood safe. Walls, cordons, and single-use zoning, whether purely residential or purely occupational, instead make a neighbourhood unsafe.

A survey found that more than 50% of people in Delhi worry about withdrawing cash from an ATM after 9 pm, and more than 90% worry specifically about a woman’s safety in the city after that hour. Mumbai’s respondents reported far lower worry on both counts.

Making a space lively is the simplest way to make it safe. The urbanist Jane Jacobs called this “eyes on the street”: when enough people watch a street, nobody can carry out a snatch, a robbery, an attack, or any other antisocial act without being reported, and the presence of watchers deters the act before it starts. A city does not need more cameras or “hired eyes,” such as private security or heavier policing, to achieve this. It needs to unlock its spaces instead, by tearing down the boundary walls and barriers that isolate one block from another, and by inviting a wider mix of uses into its blocks and neighbourhoods.

That kind of change unfolds slowly and can take many forms. A live restaurant or a karaoke bar can funnel life into one neighbourhood, and a clothing store can do the same for another. The more uses a neighbourhood mixes, the safer it tends to become. Even a gazebo, a vending cart, or a market stall can add life to a space, and street vendors and newsstands, in particular, draw patrons and footfall throughout the day. A neighbourhood built purely for housing turns out just as unsafe as a corporate park built purely for offices, or a mall built purely for shopping. Mix those uses, though, and the resulting neighbourhood fills with movement and footfall. It resists the “blight” that a dark, empty, remote street invites, the kind of boredom that becomes a den for illicit activity and harm.