Beijing has become well-known for its thick smog, with fireworks banned on Chinese New Year because of air pollution fears and commuters regularly wearing surgical masks. But pictures snapped this week in Mexico City are a reminder that dirty air is a global problem with the potential to kill millions.
Air quality in the Mexican capital has been so poor recently that on Monday government officials issued a temporary ban on 1 million vehicles, marking the first air pollution alert since 2005. Mostly older cars were targeted—a move other smog-plagued cities, such as Paris and New Delhi, have adopted over the past year.
In the 1990s, the United Nations named Mexico City, which sits in a valley ringed by volcanic mountains, the most polluted city in the world—and a more recent rollback of environmental regulations means the metropolis’ smog problems are on the uptick. Click through to see how residents are coping.