If your area uses Juniper equipment then IPv6 should be available. You could lookup the mac address of the PPPoE server and see if its of a Juniper device. If you are still on legacy systems, then no IPv6.
Sorry, yes I was referring to the equipment on BSNL's side as @Elavarasan confirmed. I think its called a BNG (Broadband Network Gateway) and an entire district can be under one or two BNGs, so its definitely not based on your local area or the LCO.
In my case it says Connected to 20:d8:0b:d4:8d:f4 via interface eth3.702 which when you do a MAC lookup shows that the prefix belongs to Juniper
This info is available when you make the PPPoE connection. Some routers display it in the UI too.
Regarding the hardware upgrade, I've been getting IPv6 since more than a year. Not all areas in Kerala are upgraded, some are still on the legacy Ericsson (I think) hardware. Perhaps the pandemic has slowed the upgrades