New Delhi, Aug. 31 -- Change happens slowly, and then all at once. And so it will be with the way a billion Indians access loans and, by extension, the way Indians access opportunity.

In 2009, such a change was unimaginable. Formal loans at scale were a quixotic moonshot-80% of adults didn't even have a bank account, let alone access to credit. Yet, quietly, the Lego blocks of a solution were laid. First, via Aadhaar's eKYC, identity verification became universally available digitally, and India opened half a billion new accounts. Then Aadhaar eSign was launched, allowing any loan agreement to be signed digitally via a mobile phone.

By 2015, DigiLocker had been introduced; it became a single window for multiple KYC affirmations and unde...