Man's impact on the environment has been an issue on Mount Everest ever since adventurers began making serious efforts to reach the summit.
Clean-up operations have made a dent in Everest's rubbish problem
This week environmental activists are making entreaties to have the Sagarmatha National Park in the Himalayas put on the World Heritage danger list, because of the threat to it posed by global warming.
But there is a more mundane issue to be addressed by those who care for this region - the increasing number of visitors and the rubbish they leave behind.
The once pristine snowscape became strewn with human waste, and earned an unflattering reputation for being the "world's highest garbage site".
Sir Chris Bonington, who led the first ascent of Everest's South-West Face in 1975, says: "We must deal with this situation. The area is one of stunning natural beauty, which is in danger of being ruined by litter."
Sir Edmund Hillary has openly admitted leaving used equipment on the slopes of Everest during his pioneering climb in 1953, when conservation was not so high on the agenda.
The issue has become much more pressing. Hundreds of people make an attempt at the world's highest peak each year, leaving oxygen tanks, food packaging and tents in their wake - excess weight discarded on the descent.
Bad for business
Recent clear-up efforts have had a real effect, says Angchering Sherpa, president of the Nepal Mountaineering Association.
The Nepalese government now makes expeditions pay a deposit, which is only returnable if they bring their rubbish back down.
2,249 people have reached the summit, "and counting"
Clean-up climbs, and financial incentives for porters to fill empty bags with mountain litter have worked, he says.
"Things are improving, the area is getting cleaner, people are much more cautious about their garbage," he says.
Those who depend on the Himalayas for a living realise "if we keep the area clean, it means more business for tour operators, local people and porters".
The Nepalese authorities are now pushing climbers to use metal containers, which can be brought down in crushed form and then recycled, rather than plastic or glass.
The collected material is fuelling local industry in Kathmandu and Jiri, where it is turned into cooking pans and utensils and sold in nearby markets.
Nepalese tourism official Summit Baral says it is not so much climbers who need to be convinced to obey the ban on plastic and glass, but the huge numbers of tourists who come to the Himalayas every year.
In 2004 there were some 379,000. They "are a bigger worry", Mr Baral says.
Sir Edmund Hillary is among those to decry the huge numbers of visitors, including inexperienced amateurs, who take advantage of improved safety and transport links to reach Base Camp, or even to set foot on the roof of the world.
While it took 30 years for the first 150 climbers to surmount Everest, the same number completed the expedition over a three-day period in 2001.
The number of successful summiteers now stands at 2,249, "and counting", says EverestNews.com.
A few weeks ago, 45 people reached the top in the same day, including a couple who got married there.
Recycled metal is fuelling markets in Nepal
Earlier this year, a helicopter pilot said he had landed on the summit.
That stunt angered some who say they want to preserve the aura of Everest, or Mount Sagarmatha as it is known locally.
The Nepalese local organisation Dharmapath Youth Club called the helicopter stunt a "heinous crime against Nepal and Nepalese sentiments and the norms and values of mountaineering spirit".
As the highest point on Earth becomes less remote, it will inevitably be difficult to balance tourism and conservation, but not everyone believes huge numbers of visitors will be detrimental.
"Unquestionably Nepal wants the money and locals want the money - they want people to come," says George Martin of EverestNews.com.
And he does not agree that Everest is now within the reach of everyone.
"Sure, anyone can go to Everest," he says. "But can you buy the summit? Well, we lose five to 10 people each year, so it's still a huge test of endurance."