Thick smog, Air pollution red alert, Beijing landmark. 重度霧霾, 空氣污染「紅色預警」, 北京地標

The Forbidden City is seen in heavy pollution on 1 December 2015 and under clear skies a day laterKevin Frayer/Getty Images

The Forbidden City is seen in heavy pollution on 1 December 2015, and under a clear sky on 2 December 2015
China: Thick smog obscures Beijing landmarks in first ever air pollution red alert
http://www.ibtimes.co.uk/china-thick-smog-obscures-beijing-landmarks-first-ever-air-pollution-red-alert-1532341

Tiananmen Square is seen in heavy pollution on 1 December 2015, and under a clear sky on 2 December 2015
China: Thick smog obscures Beijing landmarks in first ever air pollution red alert
http://www.ibtimes.co.uk/china-thick-smog-obscures-beijing-landmarks-first-ever-air-pollution-red-alert-1532341

Tiananmen Square
Photograph: Kevin Frayer/Getty Images

The Forbidden City
Photograph: Kevin Frayer/Getty Images

Beijing’s National Stadium, also known as the Bird’s Nest
Photograph: Kim Kyung-Hoon/Jason Lee/Reuters
Smog envelops Beijing: before and after pictures as city goes on red alert | Cities | The Guardian
http://www.theguardian.com/cities/gallery/2015/dec/08/beijing-air-pollution-red-alert-smog-before-after-pictures