Photos: The smog that’s choking Beijing as it faces the worst pollution of 2016

Beijing sent out its highest level of smog alert on Dec. 16 for the first time this year, suspending schools and restricting cars on the road while the city remains shrouded in a visible—and toxic—fog.

By 5 pm today (Dec. 19), Beijing’s PM 2.5, the fine particulate matter in its air, had reached 460 in some areas, according to the air quality index (AQI). The city’s 21 million citizens are wearing masks and staying indoors to protect themselves against these hazardous levels, which could have serious health effects and are expected to continue until Dec. 21.

Here are some images from a city living under a fog these last few days: