Digital Indians: Nandan Nilekani
19 September 2013 Last updated at 00:15 BST
The co-founder of India's top technology firm, Infosys, quit his company to join the government and lead a project to provide an unique ID number to a billion Indians.
The ID project is also the world's biggest biometric exercise and has faced criticism over invasion of privacy, among other things.
Nandan Nilekani talks about his journey from being one of India's most successful entrepreneurs and wealthiest citizens to working with the government on a potentially game-changing project.
And for more on this series, go to Digital Indians