>I don't know the specifics of how much identification UPI requires, but you could levy all sorts of taxes that way if you knew who was who.
UPI connects with your bank account -- that's the only way it works. So the identification that UPI has, will be same as that of what the bank account requires. Typically, higher the amount, more the IDs required to keep the account active.
> IIRC India has relatively high tax rates, but has struggled with collection in the past ....
The way tax evasion primarily happened in india was through cash payments. When you rotate money in cash, it's really hard to trace it back. Now with UPI becoming mainstream, the thing that is now accessible to govt is your day-to-day transaction history.
> once it's widely adopted enough (let's say 80/90%+ of payments)
UPI already is >80% of all consumer digital transactions (as per this article - https://bfsi.economictimes.indiatimes.com/news/fintech/upi-d... )
