UID stands for Unique Identity. The UID project was launched in India with a view to assign a unique identification number (UID) which would be 12-digit number called Aadhaar. It is issued to all Indian residents irrespective of age, gender or citizenship. The aadhaar is a proof of residence and not of citizenship. The Unique Identification Authority of India (UIDAI) established in 2016 is the statutory authority responsible for the issuance, maintenance and security of aadhaar cards to residents. This ID can also be used to avail of various government services like ration, LPG connection, pension schemes, UAN (employee PF), etc.