NEW DELHI — Hoping to clean a trash-strewn pathway to the world’s highest peak, Nepal’s tourism authority declared Monday that those climbing Mount Everest must return from the trip with an extra 18 pounds of garbage.

The rule is the government’s first concerted effort to eliminate an estimated 50 tons of trash that has been left on Mount Everest by climbers over the past six decades. The waste includes empty oxygen bottles, torn tents, discarded food containers and the bodies of climbers who died on the mountain.

Nepal’s government hopes the new rule will result in the collection of nearly eight tons of waste this year alone.

Mountaineering associations and former climbers have become increasingly concerned about the growing refuse on Mount Everest that does not degrade because of the frigid temperature. In 2010, a special team of climbers carried more than two tons of trash down from elevations exceeding 24,000 feet. And last year, concerned climbers collectively carried down four tons of trash.