Shanghai warned children and the elderly to stay indoors for a second day because of lingering smog.
The city’s air was “heavily polluted,” the second worst on a six-grade scale, the Shanghai Environmental Monitoring Center said on its website.
The concentration of PM2.5 particles -- considered the most hazardous to people’s health -- was 171.5 micrograms per cubic meter as of 7 a.m. The World Health Organization cautions against average daily exposures of more than 25 micrograms per cubic meter.
A “yellow” pollution alert remains in effect from Thursday, which has mandated special measures to suspend construction and limit factory production in city limits. The alert, which signifies a heavy pollution forecast for two days, is the third highest in a four-color warning system, according to the environmental bureau website.
Shanghai experienced several bouts of heavy pollution last month, with levels of PM 2.5 rising to their worst in two years on Dec. 15, prompting the city take emergency measures including limiting factory production.
— With assistance by Qi Ding