A Clean Break

Every week, a million more people move to cities around the world. It’s a constant, quiet migration that amounts to adding the entire population of Dublin to the planet’s urban landscape every few days. It’s easy to assume that the waste, pollution, and population booms that this rapid urbanization breeds inevitably lead to dirty cities. New Delhi’s sewage-filled rivers and Moscow’s gag-inducing air attest to that. Wealthier lifestyles mean more waste, and more people mean dirtier cities, right?

Not necessarily. Using the 2007 Mercer Consulting ranking of health and sanitation around the world, we found that the most global cities aren’t the dirtiest cities. In fact, some of the biggest, most integrated cities are some of the cleanest urban areas on the planet. Washington (11), Stockholm (24), Zurich (26), and Boston (29) rank in the cleanest top 20 of 215 cities, for example.

The problem for today’s developing giants like Lagos (53), Ho Chi Minh City (55), and Bangalore (58) is a matter of scale. Their populations are so much bigger, and their resources are scarcer, that they don’t have the luxury of decades to solve their sanitation problems. All of which means it may be harder for the next generation of cities to clean up its act.