Mount Everest's poo and wee problem
Too much poo and wee is being left behind by climbers on Mount Everest, the world's highest mountain.
It's causing pollution and could spread disease, says the boss of Nepal's mountaineering association.
Ang Tshering wants Nepal's government to ask climbers to get rid of their waste properly.
More than 700 climbers and guides spend almost two months on the mountain slopes every year.
He says that some climbers do carry disposable travel toilet bags to use in the higher camps.
At base camp there are toilet tents, which have special drums to contain human waste goes. These can be taken away from the mountain and emptied safely.