Conversation so far:
What year(s) was Mallory in Asia?
Mallory participated in the initial 1921 British Reconnaissance Expedition.
Who did he climb with in 1921?
organised and financed by the Mount Everest Committee, that explored routes up to the North Col of Mount Everest.
Were they successful in the climb?
The expedition produced the first accurate maps of the region around the mountain, as Mallory, his climbing partner Guy Bullock and E.
O.
Wheeler.
What else can you tell me about this climb?
Under Mallory's leadership, and with the assistance of around a dozen Sherpas, the group climbed several lower peaks near Everest.
Was this the only climb in Asia?
His party were almost certainly the first Westerners to view the Western Cwm at the foot of the Lhotse face, as well as charting the course of the Rongbuk Glacier.

Question: What year was this expedition?
Self-contained rewrite: What year was the expedition of North Col of Mount Everest by George Mallory and his group?