Nepal’s government has honoured two climbers who were the first to scale Mount Everest without oxygen supplies.

Minister for Tourism Rabindra Adhikari praised the climbers at a ceremony in the capital, Kathmandu, 40 years after the historic feat.

Italian Reinhold Messner and Austrian Peter Habeler reached the summit without use of supplementary oxygen, while others on their team used bottled oxygen.

Until then, all climbers carried oxygen cylinders to aid them at high altitudes where oxygen levels are low.

Since Everest was first scaled in 1953, thousands of climbers have reached the summit and hundreds more make attempts every year.

General view of Mount Everest and the Himalayas (Dominic Lipinski/PA)
General view of Mount Everest and the Himalayas (Dominic Lipinski/PA)

This year nearly 350 foreign climbers have already been issued climbing permits.

Most climbers still use supplementary oxygen.

Mr Messner has been a strong critic of the large number of people climbing Everest.

He suggested many years back that Nepal give the mountain a rest to allow it to recover, but Nepal did not listen.

“They decided like this, I cannot change it,” he said on Thursday.

However, he acknowledged climbing has been good for Nepal economically because many people stay for weeks and spend large amounts of money.

Mr Messner said climbing Everest is no longer an adventure and instead has become a tourism activity.

“Today mountaineering is tourism.

“Mountaineering is where people are going without infrastructure, but on Everest there is huge infrastructure,” he said.

“The Sherpas prepare everything and clients pay to trek to the summit.”

Everest conquerors Sir Edmund Hillary (left), Sherpa Tensing Norgay (right), pictured with Colonel John Hunt, the expedition leader, needed oxygen supplies when they scaled it in 1953 (AP)
Everest conquerors Sir Edmund Hillary (left), Sherpa Tensing Norgay (right), pictured with Colonel John Hunt, the expedition leader, needed oxygen supplies when they scaled it in 1953 (AP)

The debate about Everest climbing was revived in 2014 when 16 Sherpa guides were killed by an avalanche just above the base camp while preparing the route for clients.

A year later, an avalanche triggered by a massive earthquake killed another 19 people at the base camp.

Each climber pays the government 11,000 US dollars for a permit.

Various expedition outfitters offer climbing gear, cooks and guides, which can cost many thousands of dollars.

No mountaineering experience is required to get an Everest permit.