The first ever ‘red alert’ for poor air quality was issued for Beijing, China, by the city government due to heavy smog, multiple sources report.

This alert began on Tuesday morning and will be in effect until Thursday Reuters said.

“High pressure over the area has provided almost calm winds, allowing pollutants to build up with little to no influx of fresh air,” AccuWeather Meteorologist Tony Zartman said.

The Beijing city government ordered all outdoor construction to stop and all schools to remain closed until the smog clears.

“Construction waste, excavation transport vehicles, cement trucks, gravel transport vehicles and other large-scale vehicles are prohibited from driving on roads,” authorities added in the notice.

This poor air quality will impact the 22.5 million people who live in and around the city.

China has a four-color warning system for pollution conditions. The four levels include blue, yellow, orange and red. The four-color warning system was created in October 2013 according to Xinhuanet news.

Read the article “Beijing Air Pollution Reaches ‘Red Alert’ for First Time Ever” on foxnews.com.