"Sticking to the bottom line of ecological safety and mountaineering environmental protection, we have been strictly following the regulations of mountaineering, and an environmental protection foundation has been established to ensure that what's pure remains unpolluted," said Nyima Tsering.

"Measures such as getting the rural residents trained in mountaineering waste disposal, controlling the number of climbers and upgrading ecological protection facilities have been taken to reach the goal of environmental protection."

Tibet has been enhancing the importance of environmental protection of the mountains and large-scale cleaning activities have been organized there in the past few years.

Waste from mountaineering expeditions－including food packages, beverage bottles, discarded oxygen cylinders, old tents and excrement－has been polluting the environment.

In spring 2018, about 8 tons of waste was collected on the three mountains, and about 10.67 tons was collected in 2019.

This year marks the 45th anniversary of China's first accurate measurement of Qomolangma's height, and a comprehensive campaign of remeasuring the height of the world's highest mountain is underway this week.