Paramilitary policemen wearing masks march on a cold morning following a flag-raising ceremony amid heavy smog at Tiananmen Square in Beijing

Paramilitary policemen wearing masks march on a cold morning following a flag-raising ceremony amid heavy smog at Tiananmen Square in Beijing

Paramilitary policemen wearing masks march on a cold morning following a flag-raising ceremony amid heavy smog at Tiananmen Square, after the city issued its first ever "red alert" for air pollution, in Beijing December 9, 2015. REUTERS/Damir Sagolj/File Photo

December 15, 2016 6:36 PM (UTC+8)