Fiction moves stealthily through Payal Kapadia’s films.

The Indian filmmaker’s first movie, “Night of Knowing Nothing,” is a documentary about the student strike at the Film and Television Institute of India, Kapadia’s alma mater, following the appointment by Prime Minister Narendra Modi of a right-wing chairman. The film, though, is threaded through with fictional letters between two students who have split because they belong to separate castes.

Kapadia’s first fully narrative film, “All We Imagine as Light,” begins more like a documentary, surveying Mumbai, particularly at night, before gently gravitating toward three women, all hospital workers, who are juggling their workaday realities — and those of India’s stratified society — with their own aspirations.

“Real life is more interesting than cinema can be. We just have to pick its fruits,” Kapadia says, smiling. “There’s a quote from (Rainer Maria) Rilke that I really love: ‘If your real life is poor, it means you are not poet enough to draw from its riches.’ ”

“All We Imagine as Light,” which recently opened in select theaters and is expanding in the coming weeks, is about as rich a movie experience as you’ll find this year. The film, which won the Grand Prix (second prize) at the Cannes Film Festival in May, is an intoxicatingly atmospheric portrait of life in Mumbai — of its dreams, its illusions and its impossibilities.

As “All We Imagine as Light” moves along, it slowly accumulates the magic of fable. Prabha (Kani Kusruti) hasn’t heard from her husband, who’s working in Germany, in years. Anu (Divya Prabha), a Hindu, is in love with a Muslim man, a relationship they have to hide and that, probably, is doomed. Their slightly older, recently widowed colleague, Parvaty (Chhaya Kadam), is being evicted after many years in her apartment.

But when they escape the city — Parvaty is forced to move back to her village — the three women shed the various constrictions that grip them. They begin to imagine possibilities and see a light hidden to them by the patriarchal inequalities of Mumbai. “All We Imagine as Light,” begun in documentary, turns increasingly fictional, and yet truer.

“I wanted to get closer and closer to a dreamlike state toward the end of the film and then snap back to reality,” Kapadia says. “I wanted the first part of the film to be very kind of nonfiction, with a documentary beginning. And the second half to feel as if time slows down. The landscape changes and the feeling of light changes.”

The luminous phases of “All We Imagine as Light” has made it one of the most acclaimed films of the year — and yet, curiously, not India’s submission for best international film at the Academy Awards.

In announcing its choice — Kiran Rao’s “Laapataa Ladies” — Ravi Kottarakara, president of the Film Federation of India, explained that the selection committee felt “that they were watching a European film taking place in India, not an Indian film taking place in India.”

“What is Indian? It’s a very big continent that we have. There’s a lot of Indias,” Kapadia said in a recent interview. “I’m really happy with the film they chose. It’s a really nice film. I liked it a lot. But I feel like these kind of statements, I don’t know what purpose they serve. The committee that made the selection was 13 men. Is that very Indian? Then I don’t mind so much.”

Kapadia, 38, visited the Criterion Collection offices in New York for the interview while “All We Imagine as Light” was playing at the recent New York Film Festival. Her bag was stuffed with DVDs from a stop at the Criterion closet, including an Agnes Varda box set. Kapadia will chat naturally about arthouse inspirations or social ills, but she’s an ebullient, easy- going presence.

That her film has inspired so much emotion (the festival press screening was the rare one where attendees burst into spontaneous applause at the end) is, for her, the thing that matters most.

“What else would you want as a filmmaker, that people watch it and like it and feel something when they watch it?” Kapadia says. “As somebody who loves to go to the cinema and cry — it’s for me the greatest catharsis I can have — I just feel I want to make films where people also cry in the cinema.

“I cry a lot. I’m very easy. I’m a bit of a romantic.”

Not so unlike her characters, Kapadia is attempting to find another way as a filmmaker, operating outside the studio system of Bollywood. In Cannes, where “All We Imagine as Light” was the first Indian feature to play in competition in 30 years, she argued that Indian cinema is broader than the bigger-budget productions churned out by its state centers of industry.

“Independent filmmakers everywhere in the world, we are just a sad lot,” Kapadia says, laughing. “Everywhere we are the odd ones out. Nobody understands what we’re doing. People are like, ‘We don’t get to see your movies in cinemas. What really are you doing for five years?’ It’s a struggle for all independent filmmakers.”

Kapadia was born in Mumbai; her family has been there for generations. She attended school in southern India, and, in going back and forth to home, she was often mesmerized by Mumbai.

“There’s a sense of anonymity and freedom. It can be nice,” she says. “But it’s also a city that has extreme inequality, more and more. Since the ’80s, it’s become obnoxious, the lack of any kind of social systems (for those) who are financially struggling. That’s the really brutal part of Bombay,” the previous name for Mumbai, “the disregard for life.”

As an example, she cites a scene early in “All We Imagine as Light” — one of its documentary moments — of masses trying to get on a train at the end of a workday. An announcement is heard urging people not to sit on top of the train or they’ll be electrocuted.

“How horrible this announcement needs to be made,” she says. “People would rather risk their life just to get home in time.”

Such pressures aren’t unique to Mumbai, Kapadia notes. You could find something similar in those accustomed to living with capitalism, for example — anywhere where people struggle to realize their circumstances don’t have to be as they’re told.

“It’s about not knowing there’s another way,” she says. “We tend to work against ourselves when we don’t see that there’s another way.”