A woman and her two sons have suffocated in a remote Nepalese town after being banished to a windowless shed during the woman's menstruation.

Key points: According to a Hindu tradition, menstruating women are seen as impure or bad luck

According to a Hindu tradition, menstruating women are seen as impure or bad luck The woman was banished to the "menstruation hut" in a practice now banned under Nepalese law

The woman was banished to the "menstruation hut" in a practice now banned under Nepalese law The woman's children were aged 12 and nine

The mother, identified by local media as 35-year-old Amba Bohora, and her two sons aged nine and 12, were found wrapped together in a blanket in the morning and were believed to have died from smoke inhalation after lighting a fire to sleep by overnight, said Bajura district administrator Chetraj Baral.

"They died of suffocation because there was no ventilation and they had made the chamber airtight to beat the cold," police official Uddhav Singh Bhat said.

"We pulled out their bodies with burned limbs."

Bohora had been banished to the "menstruation hut" in temperatures well below zero in a practice known locally as chhaupadi.

The tradition, linked to Hinduism, considers menstruating women and those who have just given birth to be unclean and bringers of bad luck.

They are not permitted to enter the home, touch anyone, or eat certain foods including fruit, vegetables and milk products during this time.

The practice also dictates that mothers should give birth without assistance, adding to the region's already high maternal mortality rate.

The isolated huts make women vulnerable to extreme weather conditions, animal attacks, deadly environmental hazards and sexual violence.

Mr Baral said an investigation had started and he was consulting with government lawyers on whether to press charges against the family, who live in Budhinanda, about 400 kilometres north-west of the capital, Kathmandu.

The fight to end menstrual stigma

In August 2018, the enforcement of chhaupadi practices became a criminal offence, punishable by a three-month jail sentence and a $37 fine.

But a spokesperson for international right's group Restless Development, who work to empower youth in Nepal, said real change could only come from within the community.

"A law alone cannot end the practice of chhaupadi. Members of communities must lead the change in behaviours and attitudes that are needed to end the practice for good."

Menstrual cups are helping Nepal's girls avoid the chhaupadi ritual. ( Supplied: Clara Garcia Ortés )

Clara Garcia Ortés, founder and chief executive of Be Artsy — a group fighting to change menstrual stigma — said around 90 per cent of women in the hill districts of western Nepal still practiced chhaupadi.

"The law is not enforced," she said. "Nobody is doing anything because women are not really forced to stay outside. A lot of women feel — because they have been educated on this way — that they are really impure."

Through the Rato Baltin project, Be Artsy gave free menstrual cups and sought to educate hundreds of women and girls throughout Nepal.

But while the project has found success in some areas, with village leaders striving to end the tradition, there is still resistance.

"In some villages the huts have been destroyed, but that has not finish the practice," Ms Ortés said.

"Only the girls and women are now worse than before. Now they sleep without a hut."

Women face many hazards during their banishment to these huts. ( Supplied: Clara Garcia Ortés )

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