In Anne Lamott's book on writing, she tells a great story about facing tasks that seem overwhelming. Her 10-year-old brother was doing a big school project on birds, and as the deadline loomed, he became paralyzed by how much he still had to do. His father put his arm around him and gave him a piece of advice, "Bird by bird, buddy," he told him. "Just take it bird by bird."

This useful life lesson takes literal form in All That Breathes, a wonderful new documentary that arrives on HBO and HBO Max garlanded with international awards. Directed by Shaunak Sen — and ravishingly shot by Ben Bernhard — this inspiring film takes us inside the lives of two ordinary seeming Muslim brothers in Delhi who are actually extraordinary in their dedication to doing good in a city teetering on the edge of apocalypse.

The brothers are named Saud and Nadeem, the former friendly, the latter a little grumpy. Along with their somewhat comical sidekick, Salik, they devote themselves to a project they began as kids: protecting the bird of prey known as the black kite, a glorious, hovering creature widely detested as a scavenging nuisance. Day after day, ailing and injured kites arrive at their homemade infirmary where the trio nurses them until they're able to fly back into the urban wild.

Talk about bird by bird! The guys have helped 20,000 so far. And the injured kites just keep falling from the sky in a city whose air is infamously filthy and whose toxin-laced landfills may be the world's largest. "Delhi is a gaping wound," Saud says, "and we're just a Band-Aid on it."

Although the guys have moments of fun – they play indoor cricket – theirs is an endless, largely thankless task. We watch them do everything from fishing wounded birds out of sewagey rivers to talking butchers into selling them cheap meat to grind up as feed; they keep applying for funding that never seems to come. Making things trickier, they do this in a city charged with sectarian violence. During the filming, angry mobs kill Muslims and burn buildings in a neighborhood about a mile from their home, filling the already smoggy air with a miasma of dread.

But the movie's not grim. Working in an impressionistic style that couldn't be less strident or propagandistic, Sen has made a film that captures life in the richest and most humane sense. He immerses us in a world we didn't know before, showing us the lives of regular people, not celebrated artists or politicians. And he lets us make connections for ourselves. There's no narrator or text telling us what to think as we watch the intersection of three ecosystems.

The largest is the natural one. All That Breathes is filled with shots of Delhi's animal life — lizards, insects, dogs, rats and the city's notoriously troublesome monkeys. These creatures all are doing what the kites have done: adapting to an often-hostile environment shaped by humans. In this ecosystem, kites serve a necessary role by devouring vermin and rubbish in those huge landfills.

The second ecosystem, the social one, is demanding, especially on those who are outsiders. At this moment in Indian history, with Hindu nationalists wielding power, the outsiders are Muslims, including Nadeem, Saud and Salik. They are often treated as unwelcome, just like the kites — a metaphor that Sen lets us register but doesn't belabor.

The final ecosystem is the family, where matters can get even more complicated. It's not simply that Saud's wife gets annoyed at how he ignores his homelife, but that Nadeem and Saud themselves don't see eye to eye. Where Saud finds ecstasy in treating the birds, Nadeem dreams of going to college in the U.S. — he wants to see the world, then return even more skilled at healing. Saud thinks of this as abandonment.

Now, this is a lot for one 90-minute film, and Sen sometimes strains a bit in reaching for a grand sense of meaning. Yet this is a quibble about a film that's bursting with humanity. In an age when we're constantly reminded of all that's bad, All That Breathes celebrates good things it's easy to forget: the wonder of life, the virtues of compassion and the human capacity to make the world better.