Hazardous smog hits Shanghai as China's bad air spreads

A woman wearing a face mask walks with her dog on a bridge in front of the financial district of Pudong amid heavy smog in Shanghai, China, December 15, 2015. REUTERS/Aly Song

SHANGHAI (Reuters) - Smog in Chinese metropolis Shanghai hit its highest level since January on Tuesday, prompting schools to ban outdoor activities and authorities to limit work at construction sites and factories as polluted air spreads around the country.

Last week, hazardous pollution levels in Beijing triggered the capital's first "red alert," meaning vehicles were ordered off the roads, classes were cancelled and heavy vehicles banned.