If you attempt to climb Mount Everest, be prepared to carry down approximately 18 pounds of trash. A new law passed in Nepal mandates climbers bring down eight kilograms of garbage starting this spring. Trash buildup has been a major problem in the maintenance of Mount Everest, as exhausted climbers often leave everything from oxygen tanks to tents. "We are not asking climbers to search and pick up trash left by someone else," said Maddhu Sudan Burlakoti, head of the mountaineering department at the Tourism Ministry. "We just want them to bring back what they took up."