A huge clean-up campaign has been launched by Tibet Autonomous Region, southwest China, to remove the waste and debris left by hikers at campsites across the high-altitude area of Mount Qomolangma.

The nine-day clean-up across the mountain, which is also known as Everest, began May 6. The campsites in question are at altitudes between 5,200 and 6,500 meters on the north side of the world's highest mountain above sea level.

Nyima Cering, deputy director of Tibet sports administration, said this was the first time that the administration had worked with Tingri County government, Xigaze Prefecture, on such a campaign.

Cering said that heightened human activity had left unacceptable levels of garbage on the "Roof of the World."

He said the official team, joined by Chinese and foreign volunteers, had collected four tonnes of trash in the first five days.

He said the Tibet government planned to install sorting, recycling and degradation stations at the camping areas.

About 60,000 people visit the north face of Mt. Qomolangma every year. In their wake, they leave tin cans, plastic bags, stove equipment, discarded tents, oxygen tanks and mountain climbing paraphernalia.

Kari Kobler, president of Swiss firm Kobler, was one of the volunteers.

"I have climbed the mountain many times over the past 17 years," said the 62-year-old climbing enthusiast.

He lauded the clean-up campaign as a sign of China's increased environmental awareness.

Cering said the Tibetan government had been exploring waste disposal systems that would be suitable for the high-altitude in the hope of addressing the negative effect of human activity on the environment.