Nepal is so short of oxygen canisters that it has asked climbers on Mount Everest to bring back their empties instead of abandoning them on mountain slopes.

The country issued climbing permits to more than 700 climbers for 16 Himalayan peaks - 408 to Mount Everest - for the April-May climbing season to boost tourism. 

But Covid brought Nepal's fragile healthcare system to breaking point, as it has in neighbouring India where cases and deaths are setting records.

The Nepal Mountaineering Association said climbers and their Sherpas were estimated to have carried at least 3,500 oxygen bottles this season, but these canisters often get buried. 

"We appeal to climbers and sherpas to bring back their empty bottles wherever possible as they can be refilled and used for the treatment of the coronavirus patients who are in dire needs," they told Reuters.