The title shot of “Inversion” is an image of a metropolitan landscape so thick with smog that the skyscrapers seem to be melting right into the chalky-white air. It looks like the establishing shot of downtown L.A. that we’ve seen in a thousand films — only this isn’t Los Angeles, it’s Tehran. Iran’s capital city has yet to become a global icon of toxic air pollution on the level of, say, Beijing, but Behnam Behzadi’s new film suggests that it may be fast on its way there. (The title refers to the state of “thermal inversion” that, on bad days, pushes the poison in Tehran’s atmosphere to maximum density.) It’s an oppressive situation the citizens of Tehran simply live with, like lousy weather (or government crackdowns), but in “Inversion,” the pollution sets off a chain reaction of familial discord that closes in on the heroine, Niloofar (Sahar Dowlatshahi), until it forces her to find a new source of air.

Niloofar, a very pretty woman who has never married, owns a tailoring shop that employs a dozen workers, and early on she goes on a date with a pleasant, handsome, middle-aged fellow (Ali Reza Aghakhani), and it’s clear the two are smitten with each other. In her single-woman-in-the-city way, she seems to be living the Iranian version of the feminist dream. Her freedom, however, is illusory and provisional. She shares an apartment with her mother, Mahin (Shirin Yazdanbakhsh), who suffers from chronic pulmonary disease and is therefore not even allowed to walk through the city. But she’s stubborn and does anyway, and after one too many polluted whiffs, she collapses and lands in the hospital. The doctor’s orders: She must leave Tehran, and permanently. It’s decided that she’ll move up north and live in the vacation villa owned by one of Niloofar’s siblings. It’s also decided that Niloofar will abandon her beloved Tehran and live there with her. But even as all this is happening, the heroine starts to come to the claustrophobic realization that her entire life is now being decided for her.

Sahar Dowlatshahi is a beautiful and dynamic actress with an open, laughing face and darkly expressive doe eyes that have a way of dominating every shot they’re in. Under her head scarf, her hair lays against her forehead in a way that gives her a striking resemblance to Audrey Hepburn — and this is one case where an actress’s impish radiance serves a vital thematic function. The audience looks at Niloofar and feels so connected to her eager vitality that we want her to be everything that she can be. But she’s living in a society where that desire must take a back seat … to just about everything else.

Niloofar plans to keep running her business from out of town, but since she has agreed to leave the city, her brother, the petty brute Farhad (Ali Mosaffa), decides that he’ll pay off his debts by renting out her shop. And with the support of his other, married sister and a few additional relatives, he does. Just like that, the business that Niloofar has nurtured for 10 years — and that has nurtured her — goes up in smoke. Starting in the ’90s, the movies that emerged from the new wave of Iranian cinema — films such as Jafar Panahi’s “The Circle” (2001) — often told the story of the subjugation of women in Iranian society. “Inversion” depicts that same moral crisis in a moment of eager, precarious, baby-steps transition, with Niloofar forced to learn that as an unmarried woman seeking to go her own way, her desires have almost no value. Overnight, she loses everything, and since no one in her family appears to give a damn, this is all expressed in the storm clouds that gather across Sahar Dowlatshahi’s face.

Behzadi, who has made more than 20 films (including shorts and television productions), works in a vintage Iranian mode of what might be called the clandestine suspense of the everyday. Nothing that happens in “Inversion” is overstated or even overtly dramatized, yet there’s an invisible tension that pulls us through the movie, and that’s our investment in seeing how Niloofar can liberate herself from seemingly random events that suddenly add up to a fate that is pulling her down like quicksand. When she learns that her suitor is hiding the fact that he has a young son, the oppression of her life begins to look almost conspiratorial. How can she get herself back to a state of what felt like freedom? The missing element in her thinking, however, is her very own will; she must try to create her own “inversion.” The film ends on a note of ambiguity that may leave some audiences as puzzled as they are uplifted. (The puzzlement derives from the fact that the uplift is there … but not, perhaps, as much as we might want it to be.) Yet there’s a resonance to “Inversion” that comes from the moment in Iran it captures, when women are more liberated than they’ve ever been, but not to the point where they can totally breathe free.