Kathmandu, April 15: Australian mountaineer, Alliee Pepper, scaled Mt Annapurna-I without the use of oxygen. Pepper, 47, climbed the world’s 10th tallest peak at 12:07 pm on Sunday, said Minga Sherpa, Chairman, Seven Summit Treks Company.  Tour guides Michael Sherpa and Nima Sherpa accompanied the Australian climber. Earlier, 17-year-old Nepali mountaineer Rinzi Sherpa scaled the summit on April 12 without the use of oxygen. People’s News Monitoring Service.