BBC: Nepal's army has started work to drain rising waters in a lake near Everest at nearly 5,000m (16,400ft).
Scientists say that is vital to partially drain Lake Imja to stop it from bursting its banks with potentially devastating consequences.
Imja is one of thousands of lakes in the Himalayas formed by the melting of glaciers. But last year's earthquake may further have destabilised it.
It is the highest drainage project of its kind, the military says.
The altitude at which the work is...