Wuhan city, February 2017, in a foggy winter white as snow, all the children of the city in kindergarten are kept by the teachers in their narrow classrooms to avoid the air pollution, looking at the sky through locked glass doors. 
At a hospital lung diseases department packed with endless waves of new patients, some have been diagnosed lung cancer, and some are suffering from respiratory diseases due to the increase of air pollution during winter. Some patients even plan to leave the city to go to Sanya island in the south of China where the air is purer.  

Language: Chinese with English subtitles