For the call to get to your phone, the originating call must enter a regulated service (mobile or landline network). The entry point into the regulated service will be known as will the the metadata about the call. They can be traced, but if the origin is in India, it is very difficult to prosecute, however it has happened.I dunno. I remember hearing about scam callers in India swatting people who insulted them. Might be a little bit more difficult to trace that way.
I get lots of calls from halfway around the world using VoIP that is identified as US locations. But it's really weird because the sound quality is just so staticky even though VoIP should be clear, although possibly tinny depending on the settings.
Poor quality sound on a VoIP call is usually caused by jitter and packet loss. Delay budget can make the call herky-jerky from the other side of the world, because we aren't used to pausing and waiting to see if the far end is done or is beginning to talk.