Beijing has issued its most severe air pollution warning for only the second time ever as unhealthy levels of smog in the city are expected to persist through Tuesday.

The red alert warning, reported by state-owned CCTV News, comes just weeks after the first ever red alert since the country instituted the warning system in two years ago. The alert requires that some cars be kept off the road and orders a pause in work at some factories. School may also be cancelled at the discretion of local authorities.

Recent research has shown that pollution in China kills more than 1.5 million people each year (4,400 each day), amounting to 17% of the nation’s annual deaths. The red alert system is one of many changes instituted by the Chinese government to curb the number of deaths. The country has also committed to boosting production of energy from renewable sources that don’t pollute as much as the coal fired plants that dominate the country’s current energy landscape.

Read More: How Air Pollution Contributes to Millions of Early Deaths

Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Justin Worland at justin.worland@time.com.