Staff members dispose of kitchen waste at the Mount Qomolangma base camp in southwest China's Tibet Autonomous Region, May 3, 2020. Waste disposal facilities installed at the Mount Qomolangma base camp can meet the needs of more than 200 people per day to deal with their kitchen waste and sanitary sewage, which helps reduce the impact of human activities on the mountain environment. (Xinhua/Purbu Zhaxi)

Staff members transport kitchen waste to the waste disposal facilities at the Mount Qomolangma base camp in southwest China's Tibet Autonomous Region, May 3, 2020. Waste disposal facilities installed at the Mount Qomolangma base camp can meet the needs of more than 200 people per day to deal with their kitchen waste and sanitary sewage, which helps reduce the impact of human activities on the mountain environment. (Xinhua/Sun Fei)

Staff members transport kitchen waste to the waste disposal facilities at the Mount Qomolangma base camp in southwest China's Tibet Autonomous Region, May 3, 2020. Waste disposal facilities installed at the Mount Qomolangma base camp can meet the needs of more than 200 people per day to deal with their kitchen waste and sanitary sewage, which helps reduce the impact of human activities on the mountain environment. (Xinhua/Sun Fei)

Aerial photo taken on April 28, 2020 shows the Mount Qomolangma base camp in southwest China's Tibet Autonomous Region. Waste disposal facilities installed at the Mount Qomolangma base camp can meet the needs of more than 200 people per day to deal with their kitchen waste and sanitary sewage, which helps reduce the impact of human activities on the mountain environment. (Xinhua/Jigme Dorje)

Photo taken on May 2, 2020 shows the sanitary sewage disposal facility at the Mount Qomolangma base camp in southwest China's Tibet Autonomous Region. Waste disposal facilities installed at the Mount Qomolangma base camp can meet the needs of more than 200 people per day to deal with their kitchen waste and sanitary sewage, which helps reduce the impact of human activities on the mountain environment. (Xinhua/Jigme Dorje)