Yes, it is true! Airtel is offering unlimited prepaid planwith voice calls (local & STD), 28GB (1 GB per day max) data for a validity of 28 days and it can also be extended till one year (T&C Apply).
This is a very good offer as in Rs. 349 you can spend your almost one full month without worrying that your balance may go out. You can talk on not only local but also STD calls! Besides that, you will get 28 GBs of data, i.e., 1 GB on daily basis. You can do a lot of things in 1 GB. Play online games, play streaming music and watch movies and still you may have some data left!