Aadhaar (Hindi for ‘foundation’) is India’s ID programme, the largest in the world, surpassing 1 billion sign ups in just under 6 years. This programme aims to give every citizen a unique, biometrically-verifiable identification number. Each user receives a card with their number on it, which can be cross-referenced with the biometric data held in a government database. An Aadhaar card is not a proof of citizenship but citizens are required to provide it to receive welfare payments and social services.