World's highest garbage dump

They will concentrate their efforts between the advanced base camp at 6,400 metres and the site almost 2,000 metres higher where climbers pitch their final camps before scaling the summit.

Ken Noguchi, said there were at least 100 tonnes of litter on the higher slopes of Everest, calling it the "world's highest garbage site".

"Pollution will become even more serious in the future," he added.

Piling up

He said he planned to take the trash to Japan and South Korea and display it in public, to generate awareness about environmental degradation.

Three years ago, the Nepalese authorities banned bottles from the slopes of the world's highest mountain, in an effort to check litter from piling up.

Environmentalists have long complained about the growing mountain of litter and debris left behind by mountaineers.

A recent surge in the number of expeditions has only added to the problem, with many of the climbers poorly trained, inexperienced and...careless.

Since the peak was first scaled by Sir Edmund Hillary and Sherpa Tenzing Norgay in 1953, about 800 people have climbed Mount Everest.

Authorities say 180 climbers have died on its unpredictable slopes.