A record number of climbers are queuing up to reach the summit of Mount Everest 50 years after it was first scaled.
Poor weather has delayed the ascent of some teams
About 150 mountaineers and their accompanying Sherpas are on the south side of the world's highest peak waiting to get to the top.
Earlier on Wednesday, a Chinese team reached the peak from the north side - and broadcast the first ever live pictures from the summit.
Dangerously large numbers are expected to attempt the summit again on Wednesday night.
Junko Tabei, who in 1975 was the first woman to reach the peak of Everest, said far too many people are now trying to climb the mountain.
"Only two or three teams should be allowed in a season to climb Everest," she told AP news agency.
"The Nepalese government should cut down on the permits issued."
Weeks of impassibly strong winds have prevented anyone reaching the top of Everest this year.
But on Wednesday morning, climbers eventually made it after a clear and starlit night - just a week before the 50th anniversary of Sir Edmund Hillary and Sherpa Tenzing Norgay's historic achievement.
There was jubilation in Beijing when state television showed China's team resting at the top of the world with a Chinese flag.
"The wind is strong, extremely strong. We, the first team, are standing here expressing our best wishes to the Chinese people," one team member told hundreds of viewers at home.
Two Sherpas also reached the summit from the north side, and there are reports that other teams did as well.
But from the south side, around 100 climbers and their Sherpas were thwarted by more relentlessly high winds last night, some giving up when they were only 350 metres from the top.
They and 50 others will try again on Wednesday night, creating the potential for long waits at points on the route where only one person can go up or down at a time.
All this, in the so-called "death zone", above 8,000 metres, where the air is so thin the body stops functioning after a time.
A BBC correspondent at Everest Base Camp says many there are deeply worried that having so many people on the mountain at the same time is a recipe for disaster.