It is a 90-day promotional plan.
It seems to be active in Tamil Nadu, Kerala, Telangana, Lakshwadeep and Puducherry for now. Add any areas that I may have missed.
One article says the user will be shifted after 6 months to the 449 plan, while the other says it will happen after 90 days. Not sure who is correct. I have no idea how promotional plans work.
