Kathmandu, Jan. 13 -- Five mountaineers are on a daring mission to make a rare and extreme winter ascent of Everest without oxygen for the first time in nearly three decades.

Krzysztof Wielicki of Poland first climbed the world's tallest peak in the dead of winter on February 17, 1980. Ang Rita Sherpa, known by the epithet of Snow Leopard, has climbed Everest 10 times without using supplemental oxygen, and one of his ascents was in the winter of 1987-88.

Everest has never been climbed in winter since 1993.

During the 2019 autumn climbing season which lasts from September-November, two planned attempts on Everest, the first after a decade, failed due to poor weather conditions.

Among the five aspirants, two Germans-Jost Kobusch and Hug...