Kathmandu: A woman and her two sons suffocated to death in Nepal after she was forced to sleep in a windowless shed during her period, police said on Thursday, the latest victims of an age-old Hindu practice that was banned more than a decade ago.

Amba Bohara, 35, and her sons, aged 12 and nine, had lit a fire on Tuesday night to keep warm in the freezing mud and stone hut, but were discovered dead the next morning by her father-in-law in western Nepal’s Bajura district, police said, reports the UNB.

The practice of ‘chhaupadi’ banishes menstruating girls and women to animal sheds or huts for the duration of their period, when they are thought to be impure.

‘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 told the Thomson Reuters Foundation by phone. ‘We pulled out their bodies with burned limbs.’

The ancient tradition was outlawed in 2005, yet it remains prevalent in Nepal’s remote west. The monthly exclusion leaves women at risk of snake bites, attacks by wild animals and rape.

Some communities fear misfortune, such as a natural disaster, if menstruating women and girls are not sent away.

They are barred from touching a range of items - including milk, religious idols and cattle - and must eat frugally. Menstruating women and girls are also not allowed to meet other family members or venture out during their period.

The custom has led to several deaths, despite the government introducing three-month jail terms and fines of 3,000 rupee ($27). Last year, a woman suffocated to death after she was banished; in 2017, a teenager died after a snake bite.

Human rights activists say the government’s efforts to end the practice have been inadequate and urged tighter monitoring.

‘That a woman dies with her children during menstruation is one of the biggest tragedies,’ said Mohana Ansari of the National Human Rights Commission.

Officials say battling centuries-old attitudes is not easy.

‘The government has implemented awareness programmes to root out the practice,’ said Rudra Devi Sharma, a Women and Child Welfare ministry official. ‘But it is taking time because it needs the society and families to change their thinking.’