The Green Lake is the take off point for mountainerring expedition to the peakes of Kanchanzonga ranges.

"The hollow basin enclosed between the converging moraines of the Zemu and Green Lake glaciers has been very lately a lake and was now a lake basin"
as Douglas W Freshfield writes in his book.

The absence of lake is sufficiently companciated by splendid views around just at the foot of big mass the Khanchanzonga, beautiful peaks of mt. Simvo are just on top of you beside herds of blue sheep and couple of musk deer.