Why people are not allowed to take bath in Sikkim's Gurudongmar Lake?

Sikkim's beautiful Gurudongmar Lake is one of the highest lakes in the world. It is considered sacred by Buddhists and Sikhs, and people are not allowed to take a bath. According to ancient tales, Sikh Guru Nanak blessed the lake when he visited Sikkim. People also believed that the lake grants wishes to pregnant women who pay a visit.