12月1日，北京市区陷入重度雾霾，白昼如夜，能见度差，建筑物被“埋没”。
A traffic policeman is seen on duty wearing a mask on the Chang'an street in Beijing, capital of China, Nov. 30, 2015. Smog worsened in north China on Monday as the meteorological center upgraded its alert from yellow to orange, the second most serious alarming. (Xinhua/Luo Xiaoguang)