AT A school in Hapur, a town in the northern state of Uttar Pradesh, a teacher asks her adolescent students what periods are. The boys and girls share uncomfortable glances, shifting in their seats. One pupil eventually raises her hand. She begins to talk, making euphemistic references to “a girl’s problem”; she stutters, then stops. For the next 15 seconds, the camera lingers on her as she squirms, searching for words that don’t come. “The awkward silence is longer in the unedited film,” says Rayka Zehtabchi, the Iranian-American director of “Period. End of Sentence.”, a new documentary about women in rural India fighting the stigma of menstruation.

Relying on hand-held equipment and a sparse film crew, Ms Zehtabchi travelled to the boondocks outside Delhi to ask women about their menstrual health. Nielsen, a research firm, estimates that around 70% of women in the country cannot afford sanitary products: 300m use unhygienic alternatives like newspapers, dry leaves and cotton rags. Some 23% of girls drop out of school upon reaching puberty, humiliated by their peers and unable to access clean, private toilets.

The shame surrounding the “illness”—one description given by a young man in the documentary—is entrenched. Indian women can be barred from entering the kitchen and handling food, kept away from family members and shunned from offering prayers during what is sheepishly referred to as “that time of the month”. In 2018 a ruling by India’s Supreme Court allowing women between the ages of ten and 50 (those considered to be of menstruating age) to visit Sabarimala, a famous Hindu temple in Kerala, enraged many men. Mythology surrounding Lord Ayyappa, the god worshipped there, claims that he was celibate and disgusted by the prospect of women’s fertility. Earlier this month one person died and scores were injured as devotees protested against the judgment.

Arunachalam Muruganantham considers such vitriol bizarre. A school dropout from Tamil Nadu, a state in south India, he was horrified to discover that his wife was using dirty cloths and so set out to make sanitary towels at a fraction of the cost of the branded ones sold by multinationals. Finding that women were unwilling to give him proper feedback about his products, he fashioned a mock-up uterus from a football bladder filled with goat’s blood, with a tube that would squirt liquid into his undergarments. He would walk, cycle and run to test the limits of his design, and villagers began to shun him. Today he is fondly referred to as “Pad Man”, played by Akshay Kumar, a Bollywood superstar, in a Hindi movie by that name. His mission, he says, in a brief appearance in the documentary, is to turn “India into a 100% [sanitary] napkin-using country”.

But the main characters in “Period. End of Sentence.” are the women who learn to make these cheap sanitary products (pictured). They listen to instructions about the apparatus with eagerness. Many are housewives who embark upon a full-time job for the first time in their lives, and it demands discipline. “No one is allowed to enter the premises for gossip or chit-chat,” declares one manager.

The low-cost option looks basic, but it does the job. In an absorbency test, the product soaks up water like a sponge whereas the one available in retail stores drips and leaks. “Our pad is like a man who is not good looking but is very capable,” quips an old woman in the group who is in charge of marketing. The next step is peddling the wares door-to-door, teaching women how to use the product and convincing the local kirana (corner shop), chemists and hole-in-the-wall establishments to stock them.

Old prejudices linger still. Men turn a blind eye to the scheme; most lie when asked what they think the women are up to. “It’s some sort of a diaper making-project for babies,” says one. Another looks away, not wanting to have anything to do with it. “It will take time,” says one lady involved in the programme, “but things will change in our patriarchal society.”

A running-time longer than 24 minutes would have allowed the film-makers to consider their material in greater depth, but that is a minor quibble with a documentary that deserves a wide audience (it may now get one, given its nomination for the Academy Award for Best Documentary Short on January 22nd). The same women who are at first shown as diffident and shy become self-sufficient after setting up a factory and manufacturing 18,000 pads. One middle-aged woman buys a suit for her younger brother with her wages. Sneha, a teenage girl, chats about her hopes of becoming a police officer to save herself from the obligation of marriage. “I will have lots of money and I will fulfill my parents' dreams,” she says with a smile. “My own dreams.”