Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province. (Photos: Xinhua)

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.

Aerial photo taken on Oct. 13, 2020 shows the scenery at Zhagana scenic area in Diebu County of Gannan Tibetan Autonomous Prefecture, northwest China's Gansu Province.