Why Do People Need Bottled Oxygen For Climbing Mount Everest?

Although bottled oxygen and its usage while summiting has been largely controversial, some like George Mallory after having criticized it, made use of it during their climb. It was first used by Tenzing Norgay and Sir Edmund Hillary during their climb to the top after which it was made a compulsory requirement during the next quarter of a century.

As one climbs higher, the oxygen content in the atmosphere goes on diminishing, which then slows down the thought process which becomes exceptionally critical as one gets closer to the summit. Mountaineers using supplemental bottled oxygen have a lesser chance of physical and mental deterioration thus leading to a higher survival rate and a lesser chance of disaster.

The air is so thin that they need additional oxygen to help then breathe