Beijing issues orange alert for heavy air pollution
An orange alert means heavy pollution PM2.5 density of higher than 150 micrograms per cubic meter of air
 "Beijing issues orange alert for heavy air pollution")
The Beijing Municipality on Thursday issued an orange alert for air pollution in the next three days.
The orange alert, the second-highest in a four-tier warning system, will be effective from midnight on Thursday, according to the city air pollution emergency response office, Xinhua reported.
An orange alert means heavy pollution — PM2.5 density of higher than 150 micrograms per cubic meter of air — for three consecutive days.
When the alert is in force, outdoor activities in schools are to be cancelled, and construction projects suspended.
The smog was expected to disperse on Sunday when a cold front is forecast to hit the city, according to the city's meteorological authorities.