Six climbers from the United States, the Soviet Union and China reached the summit of Mt. Everest, the world's highest peak. The expedition was the first mounted jointly by the three nations on the 29,028-foot Himalayan peak. Bad weather delayed the climb, which had been planned for April 22 celebrations of Earth Day. Expedition members said one goal was to clean up garbage left by previous expeditions, either by burning it, burying it or hauling it down.