Nilekani co-founded Infosys and was its CEO. In 2009 he left to run a government project that most people thought couldn't work: giving every Indian a unique digital ID.
Aadhaar enrolled over a billion people within a decade. On top of it came UPI and the rest of what's called India Stack, which is why someone at a roadside stall in Bengaluru can take payment by QR code.
There are real concerns about privacy and exclusion, and he's had to argue his case in court and in public. But the idea that a government can build open digital rails, and let companies build on top, has spread to other countries.