With the debris of more than 50 years of climbing _ oxygen canisters, tents, backpacks and even some bodies _ Mount Everest has been called the world's highest garbage dump.

Now China is moving to clean up its northern side of the mountain and protect its fragile Himalayan environment, announcing a trash collection campaign that could limit the number of climbers and other visitors in 2009.

"Our target is to keep even more people from abusing Mount Everest," Zhang Yongze, Tibet's environmental protection chief was quoted Monday as saying by the Xinhua News Agency.

Everest's 29,035-foot peak _ the world's tallest _ lies on the border between China and Nepal, with climbers providing a large source of income for both countries.

However, overcrowded routes and the accumulation of debris have led to some calls for the mountain to be closed to climbers temporarily.

Last year, more than 40,000 people visited the mountain from the Chinese side, which is located in Tibet, the China Daily newspaper said. Although that number was less than 10 percent of those who went to the mountain on the southern, or Nepali, side in 2000, the paper said environmentalists estimate they could have left behind as much as 120 tons of garbage, or about 6 pounds per tourist.

There is no definitive figure on how much trash has been left on Everest in 54 years of climbing since Edmund Hillary of New Zealand and Sherpa Tenzing Norgay first conquered the mountain on May 29, 1953.

The high altitude, deep snow, icy slopes and thin air make it difficult for climbers to carry anything other than the necessities down the mountain once they reach the summit.

The Nepalese government has tightened its laws, and climbers and their guides are now required to carry out gear and trash or forfeit a $4,000 deposit.

While China isn't known to have a similar rule, it has enacted other restrictions, including forbidding vehicles from driving directly to the base camp at 16,995 feet, Zhang said. The move also was aimed at preserving the melting Rongbuk glacier, which has retreated 490 feet at the base of Everest in the past decade, he said.

Zhang said his bureau is planning on launching a refuse collecting campaign in the first half of 2009 and is urging that the number of tourists and mountaineers be restricted.

Everest featured most recently as the backdrop for the Beijing Olympic torch relay, in which a team of Chinese and Tibetan climbers carried the flame to the summit and back down. Chinese authoritieTibetan activists accused Beijing of using the climb to symbolize its control over Tibet. China says it has ruled the Himalayan region for centuries, although many Tibetans say their homeland was essentially independent for much of that time.

The 2009 date may also be politically sensitive because it falls on the 50th anniversary of the Dalai Lama's flight to India after a failed uprising against Chinese rule. The exiled spiritual leader is has long been reviled by Beijing, which recently accused his supporters for inciting bloody anti-Chinese riots in Tibet's capital of Lhasa and other Tibetan communities in neighboring provinces in March.

"We find their latest environment claim unlikely to believe, considering for example the fact that China, against international protests, paved a road to base camp for their torch event this year," Tina Sjogren, editor-in-chief of MountEverest.net, said in an e-mail to The Associated Press. She said the southern side has had pollution controls in place that work "fairly well."

The Xinhua report did not give any more details about the trash collecting campaign, and calls to Zhang's agency rang unanswered Monday.

A climbing official in Nepal said he had not received any information from China on its plans to restrict access to the mountain next year.

Mountaineering department official Ramesh Chetri said Nepal planned to keep Everest open for the 2009 spring climbing season.

"I did not hear anything about this," Ang Tshering, chairman of expedition company Asian Trekking, said by telephone from Katmandu. He said he would contact Chinese officials on Tuesday for details, and added that he did not think closing Mount Everest or limiting climbers was a good solution.

China began cleanup efforts in 2004, when 24 volunteers removed eight tons of garbage from the slopes at between 16,800 feet and 21,300 feet.

In 2005, the number of people helping out increased to 100 in hopes of making a dent in the litter, which includes abandoned tents, oxygen canisters, bottles, cans and plastic wrappers. Everest also holds the corpses of some climbers who died while trying to conquer the mountain.

Ken Noguchi, an acclaimed Japanese mountaineer, has said he has collected an estimated 19,800 pounds of garbage from both sides of the mountain in five trips, beginning in 2000.

Alton Byers, director of the Denver-based Alpine Conservation Partnership, a group that protects and restores alpine ecosystems worldwide, said Everest's litter problem is a nuisance but relatively easy to solve.

"The garbage is really cosmetic. You can pay a bunch of porters to take it out and people do that every year," he said.

Byers said one of the tougher challenges is preventing people from ripping up the local shrub juniper. Hundreds of thousands of pounds of the slow-growing shrub are harvested each year and burned as fuel by Everest climbing expeditions, resulting in soil erosion and threatening the delicate Himalayan ecosystem, Byers said.

Jon Miceler, managing director of the World Wildlife Fund's Eastern Himalayas Program, said that the southern side has suffered significant ecological damage since it opened to climbers in the 1960s.

The northern side has been less impacted because the government only began allowing international expeditions to climb there in the 1980s. But it has become increasingly popular _ and polluted _ since then.

"It's gotten to a critical point on the north side with so many more people going up," Miceler said. He listed human waste, food wrappers, old tents and spent oxygen canisters as some of the litter building up on the mountain.

"It's not an unwise thing to limit in 2009 the number of expeditions going up the north side," he said.

Zhang described the Olympic expedition as a model of environmental responsibility, saying climbers, support crews and media had carted away large amounts of garbage and relied on a pair of "environmental toilets" to keep from fouling the mountain.

Jim Whittaker, the first American to conquer Mount Everest, welcomed China's plans to limit the number of people climbing the mountain.

"You've got to have some controls on it," said Whittaker, 79. "For one thing, if you have a bottleneck on the mountain, you can get some seriously dangerous conditions." He said climbers are getting better about removing their trash, although it's not always easy to do. "You get up high on the mountain and you are lucky to get yourself off it, let alone your garbage," he said.

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