CHINA’S Gansu province was engulfed by an apocalyptic wall of sand on Sunday – watch the shocking moment the sandstorm rolled in over the city of Zhangye.
— Read on www.express.co.uk/news/world/1050724/China-sandstorm-Zhangye-wall-of-sand-Chinese-fog-China-Meteorological-Administration-Gansu

Metaphoric for the cloud of censorship overtaking the Chinese people.