Director Ritesh Batra’s debut feature film, The Lunchbox, a charming epistolary romance set in Mumbai, is steeped in nostalgia. As it traces an unlikely relationship between a curmudgeonly widower, Saajan (Irrfan Khan) and a neglected housewife, Ila (Nimrat Kaur)—all triggered by a delivery mistake, courtesy of the city’s supposedly foolproof lunch couriers, or dabbawallahs—the film also showcases the many faces of Mumbai: a frenetic, resilient, and monsoon-pelted metropolis.

While The Lunchbox has already captured hearts outside its native India, thanks to a splashy international premiere at the 2013 Cannes Film Festival (it also screened at the Sundance Film Festival last month), it hits select theaters in New York and Los Angeles tomorrow (February 28th).

T+L caught up with Batra, who regularly shuttles between Mumbai and New York, to discuss his adventures in filmmaking.

Q: What was especially challenging about shooting in a megacity like Mumbai?

A: I grew up in Bombay but left in 1998 to come to New York – when I returned to my home city recently, I realized how much it had changed. On the third day of the shoot for The Lunchbox, I acknowledged that if I didn’t embrace the chaos of the city, I would never get this film done in time. We filmed a series of scenes on local trains but because we were a small production, we weren’t big enough to hire an entire train—we just had one compartment. When we needed more extras—we never had enough!—we’d just have our security step aside and let regular commuters in.

Q: Tell us about your experience shooting with real-life dabbawallahs, or lunch couriers who are crucial to thousands of city workers?

A: Many of the montages in the film that feature the lunchbox being delivered involved shadowing a working dabbawallah. There was no other way to replicate that process: these couriers deliver thousands of lunches every day, the boxes change hands numerous times and it’s a process that relies solely on public transport. The director of photography and I put our lunchbox in an actual delivery system and followed it for a week.

Q: Both the film’s protagonists seem to be wistful for the city’s past—are there still places where visitors can glimpse “Old Bombay”?

A: There are a few Persian restaurants that still retain that feel—my favorites are Britannia Café, a Bombay institution, and Koolar Cafe, where we shot an important scene. These crumbling establishments have preserved their menus for nearly a hundred years because that’s all they really have to offer. Around where I currently live in Bandra (a suburb in West Mumbai), there’s a place called Ranwar Village that is protected by a law where you can’t construct more than you demolish. So the builders haven’t moved in and ruined it.

Q: What were your sources of inspiration for the range of dishes featured in The Lunchbox?

A: Our philosophy behind the dishes we included was that as Ila and Saajan’s relationship deepens, the recipes would get simpler. Some, like the spring apple dish, were featured for their old-world charm (it’s something only a grandmother would make) while others, like the labor-intensive bitter melon curry, were included for cinematic appeal.

Q: Were you ever hesitant about telling a story that is so specific to Mumbai?

A: When you make something so local and specific, you’re being true to a place and time. The conflicts featured in The Lunchbox are very Indian, as are the characters. But when you create something so local and pay attention to all the tiny details, you also end up uncovering something very universal.

Aarti Virani is an arts, culture & entertainment writer, covering the New York metropolitan area. You can follow her on Twitter at @aartivirani.