The “airpocalypse” of smog swirling over Chinese cities has reached its most dangerous levels yet. Beijing issued its first-ever red alert today, closing schools and taking cars off the road. How bad is it? According to EPA guidelines levels are at 6: “Everyone should avoid all outdoor exertion.”

While the short-term effects of being exposed to smog like this are scary—irregular heartbeat, asthma, respiratory problems—even lower levels can have devastating long term effects. In China, about 4,000 people die from premature deaths due to pollution every day. That’s 1.6 million people a year.

At the COP21 summit this week in Paris, China’s leaders have made some pretty significant pledges to close its coal-fired power plants, a huge contributor to the poor air quality. Let’s hope those pledges stay intact.