Delhi, India(CNN) It was a freezing January night in Nepal's far west and 17-year-old Parwati Bogati had lit a fire to keep warm as she prepared to spend the Himalayan winter night alone.
Overnight, Bogati suffocated from smoke-inhalation. Her lifeless body was found by her mother-in-law the next morning, police said.
The teenager, from Purbichauki village in western Nepal's Doti district, is believed to have been the latest victim of a centuries-old taboo that considers women and girls as unclean during menstruation.
"She had lit a fire on the floor as it was bitterly cold that night due to lower temperatures and rain," said Doti district police inspector Sundar Bam. "The blanket was charred. It appears the blanket had caught fire while she was asleep filling the room with smoke, and since the window and door were both shut, we think she died because of smoke inhalation."
The illegal custom, known as "Chhaupadi," forbids women from participating in a range of everyday activities during their periods. During this time, women are often confined to a small structure, known locally as a "menstruation hut," where they are expected to sleep every night.
Bogati is at least the fourth victim of the practice to have died this year. On January 9, Amba Bohora, 35, and her sons aged seven and nine, were found dead from suspected smoke inhalation in neighboring Bajura district after lighting a fire in a tiny wooden menstruation hut.
But police said Bogati was not banished to a hut. Instead, she was sleeping in small unused room of a house belonging to her in-laws.
Since Chhaupadi was criminalized in 2017, police inspector Bam said the practice "has been largely eradicated" in Doti district. But campaigners say Bogati's death shows that women and girls are still being isolated because of a normal bodily function and the stigma surrounding menstruation remains deadly.
"Earlier (women) were confined in a separate hut, but now that a lot of them have been demolished, they are finding different places in the house to be isolated," said prominent Nepali writer and menstrual rights activist Radha Paudel. "The segregation continues. They still cannot participate in household activities during the menstruation."
Chhaupadi dates back centuries and has its roots in Hindu taboos over menstruation.
As well as being isolated in huts, women and girls are forbidden from touching other people, cattle, green vegetables and plants, fruits, according to a 2011 United Nations report. They are also not allowed to drink milk or eat milk products and their access to water taps and wells is limited.
"Some in the Far West (of Nepal) still believe that a God or Goddess may be angered if the practice is violated, which could result in a shorter life, the death of livestock or destruction of crops," the report said.
In some areas, the restrictions extend to girls reading, writing or touching books during menstruation out of fear of angering Saraswati, the goddess of education.
Paudel said the "main issue" that needs to be tackled is this concept of impurity. "A girl during menstruation is impure and she needs to be isolated -- as long as that concept is there, it's very difficult to root out the problem."
The practice has resulted in a number of high-profile deaths in recent years, typically from snake bites or smoke inhalation, especially during the freezing winter months. Most huts have no ventilation, making fires particularly risky.
Campaigners say the law, which levies a three month imprisonment or a $30 fine to anyone found forcing a woman into a menstrual hut, is not enough to end the stigma around periods.
They say more needs to be done to remove associations of shame surrounding mensuration and men and women alike need to be educated about the potential dangers of the tradition.
"The menstruation huts are being destroyed, but that's not the only solution: The mentality needs to change," said lawmaker Amrita Thapa, who was part of a six-member parliamentary team that conducted a field study of Chhaupadi in Nepal's far west in the wake of the recent deaths.
"We have found three things: There is a clear lack of awareness about this issue, tradition and superstition is deeply rooted in the society, and the entrenched patriarchy is also hugely responsible," she said.
Thapa said that part of the problem was that women themselves believe they should follow the tradition. "In many cases, the women are not forced to be isolated," she said.
Nepal recently asked all district administrations to submit a report on their plans to tackle the practice, according to Ekadev Adhikari, Information Officer for the Ministry of Home Affairs.
In Dadeldhura district, which borders India, some village councils have started denying government services, such as financial allowances and birth registrations, to families that do not send their daughters school during their periods or have a menstruation hut, chief district officer Mohan Joshi told CNN. Similar initiatives are also being considered in nearby Acchaam.
But to really begin changing deeply entrenched attitudes, activists said a holistic approach is needed.
"It is a complex issue. It's an issue of disempowerment, violation of women's rights ... issue of health, education, environment, water, sanitation and hygiene. Focusing on just one aspect won't solve the problem or transform the situation," Paudel said.
"We have to erase the fear inside people that menstruation means bad luck."
Paudel believes that starting a dialogue and engaging with everyone in the villages -- including men, women, teachers and health workers -- will help "unveil the issue."
Even teachers and health workers in these areas, she said, are not equipped with the understanding of menstruation as a biological science.
"They never talk about this issue at home or school. Until and unless we make them understand menstruation is a natural thing and there is nothing unholy about it, only demolishing huts do not solve the problem," she said.
"We need to educate this group as well."