India, Dec. 24 -- As India's payments digital public infrastructure approaches its tenth anniversary, the Unified Payments Interface (UPI) continues to stand out for its scale and adoption. In November alone, it processed over 20 billion transactions. As estimated by experts, UPI has 491 million unique users and serves close to half of India's total addressable population. Its role in reshaping everyday transactions is evident. Yet, important questions remain: Who are the millions still not using UPI, and why? And is there public data that can point us toward the answers?

These questions matter because the next phase of UPI's growth depends on a deeper focus on inclusion and innovation. Reaching those who remain outside it needs a cleare...