A group of musicians traveling from Lahore to New York to perform their version of jazz orchestra take a break to watch a busker at Times Square make music with upturned plastic buckets. “He’s a poor musician, just like us!,” says one of them, fishing out some money from his pocket.

Song of Lahore, a documentary by Sharmeen Obaid Chinoy and Andy Sohocken, follows the musicians of the Sachal Jazz Ensemble from the Pakistani metropolis to the Lincoln Center in New York City, where they perform with renowned trumpet player Wynton Marsalis. The group, founded by millionaire Izzat Majeed, re-imagines western jazz classics by incorporating the sounds of the subcontinent and using such instruments as the tabla, dholak, flute and sitar. The ensemble's re-working of Dave Brubeck’s classic Take Five prompted the jazz legend to exclaim that it was the most interesting and different recording of Take Five he had ever heard.

The group has released two music albums, Sachal Jazz (2011) and Jazz And All That (2013), and also run a Youtube channel where they enthrall listeners with their covers, including Bulleh Shah's Dama Dam Mast Qalandar, R.E.M's Everybody Hurts and The Beatles' Eleanor Rigby.

In this clip, the ensemble re-interprets John Lennon's Imagine, blending western and Asian instruments. The jugalbandi between the tabla, sitar, and other western instruments, including violins and guitars, lends an eclectic and yet harmonious spirit to the beautiful song about peace and unity.

In the trailer for the documentary, one musician recounts how their musical traditions have faced severe threats from religious extremists since the 1980s. The band was formed when the London-based Izzat Majeed decided to recreate the music of the 1960s, which had began to decline under the dictatorship of Pakistani dictator Zia ul-Haq.

Majeed went around looking for the artists in vegetable markets and at tea shops. He says, “They were getting on in age, they’d stopped teaching their children how to play, and they were surviving however they could. They’d just given up, because they didn’t see any future in music.”

In 2005, Majeed paid two million pounds to build the state-of-the-art Sachal Studios, where he assembled the ensemble that has since grown into a sensation.

When its time has come, music cannot be stopped. The Pakistani band wasn’t granted permission last year to perform at Mumbai’s National Centre for the Performing Arts. Song of Lahore flows freely through the air.