Here are the Plan Details of Airtel 4G LTE Wireless Internet Broadband in Kolkata
Airtel 4G LTE breakfree Rs 999 6GB Data Usage
Airtel 4G LTE breakfree max Rs 1399 9GB Data Usage
Airtel 4G LTE breakfree ultra Rs 1999 18 GB Data Usage
All the above Plans Come with Fair Usage Policy. The moment you exceed the Quota Allotted in the usage, Speed will drop to 128 Kbps.
Do let us know what is the speed you are getting doing a Airtel 4G Speedtest here