Drones clean up Everest

Flying garbage collectors are helping to tackle Mount Everest's waste problem.

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Since the first attempt to reach the mountain's summit in 1922, climbing expeditions have ditched tents, oxygen tanks, food containers and other rubbish. Each year, about 1,000 foreign climbers attempt to scale the mountain from the Nepal side, which is the most popular route. Some estimates suggest that they each leave behind about eight kilograms of waste.