Yellow alert pollution warning in Beijing

 A yellow alert was issued in Beijing, warning residents of air pollution. Yellow alert indicates the average daily air quality index will exceed 200 for at least two days.

The China National Environmental Monitoring Centre said the central and southern parts of the capital would be affected by the pollution. Moderately or seriously polluted air will engulf the city till Friday, when the quality of air is expected to improve.
The authorities imposed restrictions on Wednesday, including dust control at construction sites, suspension of construction work and restrictions on vehicle movement.
China has a four-tier warning system where red reflects most severe conditions, followed by orange, yellow and blue. Chinese cities are frequently choked with high levels of smog.
The multi-level warning system was introduced a few years ago to warn residents of the threat of pollution.
The yellow alert warns of an air quality index of more than 150 micrograms of harmful fine particulate matter per cubic metre of air for two consecutive days.