Officials have not been able to estimate exactly how much rubbish is on Everest, as some is still covered by snow.

A Nepal government expedition to Mount Everest has removed 11 tonnes of rubbish and four dead bodies from the world’s highest mountain, officials said on Wednesday.

Climbers returning from the 8,850-metre-high mountain say its slopes are littered with human excrement, used oxygen bottles, torn tents, ropes, broken ladders, cans and plastic wrappers left behind by climbers – an embarrassment for a country that earns valuable revenue from Everest expeditions.

Some of the rubbish was flown to Kathmandu and handed over to recyclers in a ceremony on Wednesday, officially concluding the cleaning campaign. Officials called it a successful mission but said more rubbish still needs to be collected. Some is covered by snow and only is exposed when temperatures rise.

Officials have not been able to estimate exactly how much rubbish is on the mountain. Most was at Camps 2 and 3, at which climbers can rest along the way between the base camp and the summit.

Workers from a recycling company display the rubbish collected and brought from Mount Everest [Navesh Chitrakar/Reuters]

A clean-up team of 20 Sherpa climbers collected five tonnes of litter in April and May from different camps sites above the base camp and another six tonnes from the areas below, said Dandu Raj Ghimire, director general of the Department of Tourism.

“Unfortunately, some garbage collected in bags at the South Col could not be brought down due to bad weather,” Ghimire said in a statement on Wednesday.

The four bodies were exposed by melting snow and were carried to base camp and then flown to a hospital in Kathmandu for identification, Ghimire said.

Climbers struggling to make it down the mountain alive sometimes are unable to carry out the bodies of teammates who have died.

‘Death zone’

Nine mountaineers died on the Nepali side of Everest in May while two perished on the Tibetan side, making it the deadliest climbing season since 2015.

Climbers returning from Everest have talked of crowding and delays on the Nepali side just below the summit in the “death zone”, so-called because at that altitude the lack of oxygen can be fatal. However, climbers and guides have blamed a host of factors for the deaths.

More than 300 climbers have died on Everest since it was first conquered in 1953. It is unclear how many bodies are still on the mountain, and officials said they have no records.

Hundreds of climbers and their guides and porters spend weeks on Everest every spring, the best climbing season. A tent city rises at the base camp at 5,300 metres for three months between March and May.

Nepal this year issued 381 permits to Everest, costing $11,000 each, an important source of income for the cash-strapped nation.