Beijing is currently grappling with a “red alert” fog warning, causing flights to be grounded, schools to shut, and highways to empty. Even by the Chinese capital’s notoriously smoggy standards, it’s bad.

Chas Pope, a British guy working in China, managed to capture a 13-second timelapse of the “airpocalypse” coming into the city within just 20 minutes on Tuesday. Pope filmed the video from the window of his office block by simply using the timelapse feature on his smartphone. Although he’s been working in the same building for 13 years, he said this is the first time he’s ever seen the smog so heavy.

As TreeHugger points out, the Real Time Air Quality Index for Beijing appears to show a massive spike at the time the video was shot.

The winter season brings even heavier pollution than the rest of year, when there's an increase in coal burning in order to heat homes. This bout of smog is expected to stick around until a cold front drives it out next week.

The fine particulate content of the smog comes with a host of long-term health impacts for those living in Beijing, primarily lower respiratory infections and lung cancer. Worldwide, outdoor air pollution causes over 3 million premature death each year. Around 40 percent of those deaths are in China alone.

The Chinese government has repeatedly declared a “war" on air pollution over the past few years. Although they're currently in the midst of a clean energy revolution, which is seeing the construction of two wind turbines every hour, there’s still a long way to go.