The girls who are forced to sleep in animal sheds when they're having their period.

It was winter in Nepal, and 15-year-old Roshani Tiruwa was spending the night by herself in an animal shed. She hadn’t done anything wrong. She was just having her period.

In rural areas of western Nepal, many families follow the centuries-old practice of banishing girls and women from the home when they’re menstruating because they’re believed to be “impure”.

Tiruwa was trying to keep warm. She lit a fire inside the mud-and-stone hut, but it had no chimney or any other ventilation. She died from smoke inhalation. In the morning, her father found her body.

Tiruwa was the second girl to die within a four-week period last year due to the practice, which is known as chhaupadi.

This year, there have been more victims. Lalsara Bika, 14, died from a cold-related illness she picked up while sleeping in an animal shed. Tulasi Shahi, 19, died when she was bitten on the head and leg by a poisonous snake.

Other young women have been raped or abducted by men taking advantage of their vulnerability.

As well as being forced to sleep in huts, girls and women having their period have to do outdoor labour during the day. They’re restricted in who they can mix with, and only given limited food. Many are also banned from reading and writing. Most of them report feeling lonely and scared.

“I feel horrible here – the cow dung smells and the animals step on us,” Sofalta Rokaya, 16, told The Guardian. “The dirt and hay get stuck all over my body.”

Women who have just given birth are also banished, along with their newborns. This contributes to a high mortality rate for both mothers and babies.

Laxmi Raut endured a freezing cowshed with her newborn daughter. The little girl died when she was just 18 days old.

Chhaupadi is, in some ways, linked to the Hindu religion. Families who practice chhaupadi are said to fear that gods will be angered if the rules aren’t kept and women stay in the family home while having their period. Some believe not adhering to the practice could result in death or disaster. Some people believe that if a menstruating woman fetches water, the well will dry up, and if she touches a crop, it will wilt.

Officially, chhaupadi was outlawed by the Supreme Court of Nepal in 2005, but like many harmful cultural traditions, has proven difficult to eradicate. Last year, Radha Paudel from Action Works Nepal claimed that up to 95 per cent of women in some regions of the country were still practicing chhaupadi.

LISTEN: A man has invented a solution to women's periods.

In August this year, Nepal’s parliament introduced penalties for anyone forcing a woman into a menstrual hut – a $US30 fine or three months’ jail.

But for the penalties to have an effect, people have to be aware they exist and be prepared to report the crime. The Kathmandu Post reported this week that many girls and women in remote villages still weren’t aware of the new penalties.

The newspaper also spoke to Ganga Bahadur Dhami, who is continuing to banish his 15-year-old daughter to a cowshed. He says it’s impossible to stop the practice.

“We are God-fearing people,” he said. “If we allow women to stay in the house during their period, it will invite bad omen and disease. Will law save us from diseases and illnesses? Only God will.”