Beijing officials declared a first-ever “red alert” for smog. The officials warned China’s capital would be covered in heavy smog from Tuesday to Thursday.

In an online statement, the Beijing government ordered all outdoor construction work to stop on those days. The government is also urging schools to close. The notice also limits traffic for some types of cars. Beijing residents took to the Internet to criticize the government. Many said the government should have ordered a red alert earlier. Beijing had been under an orange alert last week.

On Chinese social media, one user asked, “If today is a red alert, then what was it I was seeing last week?” China has a four-color warning system for air pollution: Blue, Yellow, Orange, and Red - the highest alert. Phrases like “Beijing Pollution” and “China Pollution” trended on Facebook and Twitter. Twitter user Sean Broderick wrote, “I guess they were shamed into doing a Red Alert.” And Leslie Montgomery tweeted: “They are poisoning their world.