Another name for the South Col
on Mount Everest
See siege tactics
if you want to know why.
Most climbers going for the summit have a camp at the South Col. When stumbling down from their sometimes successful, sometimes not, summit attempts, they don't feel like picking up their tents, oxygen canisters, toilet paper and whatever they've managed to drag up there. At 14,000 feet it takes 40 years for toilet paper to decompose. At South Col's 26,000+ feet, nothing does.
Every year nowadays, there at least one cleanup expedition trying to at least clean what's been left the very same year.