Procedure To Check Your 2G GPRS Data Balance For All Operators

Here is the procedure to check the 2G data usage balance for all telecom operators.
Please let me know through comments if there are any mistakes in the list.
Aircel: Dial *111*10#
Airtel:Dial *123*10#
BSNL: Send SMS DATA2G to 53733
Tata Docomo(GSM): Dial *191#
Vodafone: Dail *111# and select option 6
Reliance (GSM): send SMS BBAL your mobile number to 53535
Idea: send SMS USAGE to 58880
Videocon: Dial *123#

source:http://www.worldofgprs.com/2013/04/procedure-to-check-your-2g-gprs-data-balance-for-all-operators/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+WorldOfGprs+%28WORLD+OF+GPRS%29