An acclaimed Japanese mountaineer brought down 500 kilos of garbage from Mount Qomolangma in his latest campaign to clean the world's highest mountain.

It was the fifth trip by Ken Noguchi, who began his clean up campaign in the year 2000.

During these five trips, he has collected an estimated 9,000 kilos of garbage from both sides of the mountain - the northern side in China and southern side in Nepal.

Now Noguchi, who was aided by two other Japanese mountaineers and 12 Sherpa guides, thinks Qomolangma is much cleaner than before because more people are aware of the impact of leaving garbage on the mountain.

"During this year's clean-up expedition, I found that the amount of waste left on the mountain has drastically decreased," Noguchi told reporters yesterday. Noguchi says he's collected an estimated 8,981 kilos of garbage over the course of his five trips.

Although estimates vary, some say there are 50 tons of trash on the mountain - left behind over 54 years of climbing since New Zealander Edmund Hillary and Sherpa Tenzing Norgay first conquered Qomolangma on May 29, 1953.

The high altitude, deep snow, icy slopes and low level of oxygen make it difficult for climbers to carry anything other than the necessities down the mountain once they reach the peak.

As a result, Qomolangma has been nicknamed the world's highest garbage dump. In recent years, however, the Nepalese government has tightened its laws, and climbers and their guides are now required to carry out gear - tents, ropes, sleeping bags, oxygen tanks - and trash or forfeit a $4,000 deposit.

There have been several expeditions to clean up Qomolangma in the past, but some have been accused of concentrating more on scaling the peak than on bringing down garbage.