One-and- a-half years ago, Prabha Atre delivered a Carnatic raga towards the end of a concert she gave at Nagpur in her native Maharashtra. It’s not as if south Indian classical tunes never figure in a Hindustani concert (there are many common ones too), yet the veteran vocalist’s choice stood out for its distinct flavour. It was Sarasangi, a melody-type largely unfamiliar to the music-lovers north of the Deccan.