Aerial photo taken on Oct. 17, 2019 shows part of the snow-covered No. 318 national highway on Jianziwan mountain on the Sichuan-Tibet highway. (Xinhua/Jiang Hongjing)

Aerial photo taken on Oct. 23, 2019 shows part of Nujiang River zigzag road on the Sichuan-Tibet highway in Baxoi County, southwest China`s Tibet Autonomous Region. (Xinhua/Jiang Hongjing)

Aerial photo taken on Oct. 23, 2019 shows part of the No. 318 national highway on Jueba mountain on the Sichuan-Tibet highway. (Xinhua/Jiang Hongjing)

Aerial photo taken on Oct. 24, 2019 shows part of the Sichuan-Tibet highway in Bomi County, southwest China`s Tibet Autonomous Region. (Xinhua/Jiang Hongjing)

Aerial photo taken on Oct. 24, 2019 shows part of the No. 318 national highway on Sejila mountain on the Sichuan-Tibet highway. (Xinhua/Jiang Hongjing)

Photo taken on Oct. 30, 2019 shows part of the No. 317 national highway on Xiela mountain on the Sichuan-Tibet highway. (Xinhua/Jiang Hongjing)

Aerial photo taken on Oct. 15, 2019 shows part of the No. 318 national highway on Erlang mountain on the Sichuan-Tibet highway. (Xinhua/Jiang Hongjing)

Aerial photo taken on Oct. 17, 2019 shows part of the snow-covered No. 318 national highway on Jianziwan mountain on the Sichuan-Tibet highway. (Xinhua/Jiang Hongjing)