Aadhaar which means 'foundation' is a unique 12-digit identity number issued to all residents of India based on their biometric and demographic data. The data is collected by the Unique Identification Authority of India (UIDAI) a legal authority established in January 2009 by the Government of India under the Ministry of Electronics and Information Technology in accordance with the provisions of Aadhaar (Directed delivery of financial services and other subsidies, benefits and services law) 2016.
Aadhaar is the largest biometric identification system in the world, with more than 1,171 billion members registered until August 15, 2017. As of this date, more than 99% of Indians aged 18 and over had been registered. in Aadhaar. The World Bank's chief economist, Paul Romer, described Aadhar as "the most sophisticated identification program in [the] world."
Before the enactment of the Law, UIDAI functioned as an adjunct office of the Planning Commission (now NITI Aayog) from January 28, 2009. On March 3, 2016, a monetary law was presented in Parliament to provide support legislative to Aadhaar. On March 11, 2016, the Aadhaar Law (Specific Delivery of Finance and other Grants, Benefits and Services) of 2016 in Lok Sabha was approved. On March 26, 2016, this Act was notified in the Gazette of India.
Aadhaar is proof of residency and not proof of citizenship. In itself, it does not grant any right to domicile in India. In June 2017, the Ministry of the Interior clarified that Aadhaar is not a valid identification document for Indians traveling to Nepal and Bhutan. Despite the comparisons, the Aadhaar project in India is nothing like the US social security number because it has more uses and fewer safeguards.