Aerial photo taken on Jan. 22, 2019 shows the fog scenery in Wanshan District of Tongren City, southwest China's Guizhou Province. (Xinhua/Wu Weidong)

Aerial photo taken on Jan. 22, 2019 shows the fog scenery in Wanshan District of Tongren City, southwest China's Guizhou Province. (Xinhua/Wu Weidong)

Aerial photo taken on Jan. 22, 2019 shows the fog scenery in Wanshan District of Tongren City, southwest China's Guizhou Province. (Xinhua/Wu Weidong)

Aerial photo taken on Jan. 22, 2019 shows the fog scenery in Wanshan District of Tongren City, southwest China's Guizhou Province. (Xinhua/Wu Weidong)

Aerial photo taken on Jan. 22, 2019 shows the fog scenery in Wanshan District of Tongren City, southwest China's Guizhou Province. (Xinhua/Wu Weidong)