[amf12]

Indian POSes expect pins and most international credit cards do not have one so they get auto-decline

This is actually an America problem and not a world problem. Even cards and POS in Europe are chip enabled. On the other hand, I have used my PIN-less American credit card in Europe and India and it always worked without asking for a PIN.

Indian websites accepting online payments are usually extremely poorly designed and can't handle International credit cards at all. Most even require that you must have Indian phone number.

+1, the entire online banking experience sucks.

buy Internet access on international airports in India. It is impossible unlike rest of the world. The worst thing is that to even get in the Indian payment system you need govt issued citizenship documents and wait for approvals

That's not true. There are cell-phone service providers on the Airport that issue you a working SIM with an international passport on the spot. You don't need Indian citizenship. But you do need an Indian bank account for UPI.