The authorities in Southwest China's Tibet Autonomous Region kicked off an annual campaign Saturday to clean up rubbish left by climbers on the north slope of the world's highest peak, Mount Qomolangma.

The campaign will last for nine days and focus on campsites between 5,200 and 6,500 meters above sea level, the area that is scattered with the most trash, the China News Service reported Saturday, citing staff from the Tibet Mountaineering Association.

The campaign is being jointly carried out by national and regional mountaineering associations, the Tibet sports bureau and local governments. More than 90 people will participate in the clean-up.

Much of the garbage scattered on the slopes of the mountain, commonly known in the West as Mount Everest, is made up of bottles, cans, food packaging, tents, oxygen tanks and climbing ropes.

More than 4,000 climbers have scaled Mount Qomolangma since New Zealand's Edmund Hillary became the first person to do so in 1953. Since April, over 210 climbers have attempted to scale the mountain from the north side. 

As the number of visitors grows, the authorities are working to protect the mountain and the wider region.

The Tibet forestry bureau said in a circular Friday that it has banned visitors from passing through the Changtang National Nature Reserve - China's biggest and highest reserve - to access other areas, especially two other nature reserves, one in Xinjiang and another in Qinghai, as a measure to protect the environment, the Xinhua News Agency reported.

It called on tourists, adventurers and tourism agencies to comply with the reserve's laws and regulations to "protect the last pure land on earth."