New Delhi (CNN) A Nepali mother and her two children were found dead Wednesday morning, after being exiled from their family home as part of a criminalized practice where women and girls are made to sleep alone when menstruating.

In sub-zero winter temperatures, Amba Bohora, 35, and her sons aged seven and nine, are believed to have constructed a small fire inside a tiny wooden hut close to their home in rural western Nepal. By the morning all three were dead.

"They are suspected to have died from smoke inhalation," Uddhab Singh Bhatt, the area's senior police officer, told CNN.

Bohora was taking part in chhaupadi, a common practice in the west of the country in which women, considered unclean during menstruation, are forbidden from touching other people, food that may be consumed by others, cattle and even books.

They are confined to a small structure, called a menstruation hut, where women are expected to sleep every night, even during Himalayan winters.

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