The Aadhaar (which translates to ‘foundation’ in Hindi) is a 12-digit identity number that Indian residents may (presently) choose to obtain. Residents who enrol with the the Unique Identification Authority of India to receive an Aadhaar are also provided a registration card, and are required to submit certain biometric and demographic data, including fingerprints and iris scans. This card serves as a valid proof of residence rather than citizenship. Importantly, the ease with which Aadhaar cards can be cross-referenced to such data has attracted much praise—the World Bank Chief Economic Paul Romer, for example, described it as the ‘most sophisticated ID programme in the world’. Since their introduction, Aadhaar cards have increased exponentially in popularity, but now their widespread use (which is in some cases compulsory) means proportionality analysis has become a necessity.