KATHMANDU: Polish alpinist Bartosz Kacper Ziemski successfully summited Mount Everest on Tuesday without supplemental oxygen before skiing down toward Base Camp, marking a historic achievement in Himalayan mountaineering.

Just a week earlier, on May 12, Ziemski had also completed a no-oxygen summit and full ski descent of Lhotse. With the back-to-back accomplishments, he became the first person in history to complete ski descents of both Everest and Lhotse without oxygen in a single climbing season.

Ziemski carried out both ascents in alpine style, climbing without Sherpa support or bottled oxygen.

His Himalayan ski-mountaineering record also includes successful descents from Annapurna I, Kangchenjunga, Dhaulagiri, Makalu, Manaslu, Gasherbrum I, and Broad Peak, further cementing his reputation as one of the leading high-altitude ski alpinists in the world.