In his book 'Back to Bharat: In Search of a Sustainable Future', impact investor Nagaraja Prakasam distinguishes between India and Bharat. For him, the word 'Bharat' means the "ignored billion" in the country. These are people, he says, that are still largely left out of the digital revolution—venture investors are mostly wary of them, and businesses stay away as they do not see profit in solving for them. Prakasam, partner, Acumen Fund, has spent his time backing social enterprises. He talks to Divya Shekhar about his new book and life choices