Guwahati, Aug. 31 -- In 1999, something happened in Assamese music that would never happen again. Zubeen Garg and Bhupen Hazarika, two of the most distinctive voices the region has ever produced, came together on a single album.

That album was Xopun, and for those who know its backstory, it carries an emotional weight that goes far beyond the music itself.

Released under RK Productions, Xopun blended blues, pop, and classical sensibilities into eight songs that spanned generations of Assamese musical thought. The two voices could not have been more different in texture and era, yet the album holds together as a coherent piece of work, partly because it was built around something deeper than a commercial collaboration.

The album was, at...