It took more than 50 followup calls to Airtel and their reseller to get my 4G router activated. The 4G does NOT work properly even in Gurgaon, a prime location in NCR. And the data usage limit 6 GB exhausted within a week, whereas I did only normal browsing.
It is ONLY an advertising gimmick to lure customers, please do NOT fall prey to Airtel.
I am going to switch back to my old Photon-Max 3G dongle.