Beijing issued a blue alert for heavy air pollution on Wednesday as a new round of smog hit the city, authorities said.
The alert, effective from 4 p.m., is forecast to last one day, according to a statement by the city's air pollution emergency response office.
Air quality will improve Thursday afternoon when a cold front is expected, according to the statement.
Beijing has a four-tier color alert system for pollution, with red the highest, followed by orange, yellow and blue.
