BEIJING, March 24 (Xinhua) -- Beijing issued an orange alert over air pollution Saturday night.

The air pollution is to last from Monday to Wednesday, said Beijing's air pollution emergency response office.

The central part of the Beijing-Tianjin-Hebei region is forecast to see moderate to severe air pollution during the period, with the air quality index (AQI) in some regions to exceed 300, according to the China National Environmental Monitoring Center.

Under China's four-tier warning system, red is the most severe, followed by orange, yellow and blue.