Millions of users are affected by this meltdown since PhonePe, an Indian payments app has partnered only with Yes Bank while it's competitors partnered with multiple banks.
Yes Bank launched PhonePe on Day 0 of UPI. The whole multiple bank thing was made possible much later via NPCI because of Google Pay.
I wouldn't blame them for it. And they managed to get back up in 24 hours, which is pretty decent. (The Bank itself is still down, but payments via PhonePe are functional as long as you have a non-yesbank account)
PhonePe is a cool app, which a lot of people, especially small time vendors accept.
I pretty much use PhonePe for everything these days.