Tibetan authorities have launched a massive clean-up operation to remove waste left by hikers at campsites across the high-altitude area of Mount Everest.
The nine-day operation across the mountain began on May 6. The campsites in question are at altitudes between 5,200 and 6,500 metres above sea level on the north side, Xinhua news agency reported.
Nyima Cering, Deputy Director of Tibet Sports Administration, on Thursday said that heightened human activity had left unacceptable levels of garbage on the "Roof of the World".
He said the official team, joined by Chinese and other foreign volunteers, had collected four tonnes of trash in the first five days.
He said the Tibetan government also planned to install sorting, recycling and degradation stations at the camping areas.
About 60,000 people visit the north face of Mount Everest every year.
They leave tin cans, plastic bags, stove equipment, discarded tents, oxygen tanks and mountain climbing tools.