The Chief Minister of Delhi has been aggressively promoting the registration of Aadhaar, the Unique Identification Number that every citizen should have. It is a 12 digit number which you should be able to get from any nearest Aadhaar registration center. This number will serve as a proof of identity.
This number will be issued free of cost and will be recognized all over India, it will help you in opening bank account, get you mobile connections etc.
For more info please call toll free on 1800 180 1947