How to activate Airtel free missed call alert for 90 days

So, now we are back again with another Airtel trick for free missed call alerts.Please note : It may or may not work in your circle. So keep your balance low and try it on your own risk.

Airtel trick to activate free missed call alert for 90 days

1. Dial *321*881# and press 1 to confirm the offer.
2. Now, you will get free missed call alerts for 90 days from the date of activation.
3. Confirmed in Rajasthan, Bihar , Mumbai, Andhra Pradesh, UP east (other circles will be listed soon.)