Please be very cautious and aware of what you might loose porting to Airtel. I have been on Vodafone for a long while and ported to Airtel a few weeks back.
You end up loosing far more than you gain. Your credit limit, your international dial access and most importantly their customer service is a bureaucratic nightmare. They take a few good days to respond( the website says within 24 hours) and the answers are the same, much like our favourite pet parrot.
As a feedback: do not get taken in by the 4G advertisement; they offer far less than they promise.