Aadhaar: Identity at Scale

How India built the world's largest biometric identity system, what it is used for, and the privacy debate that reached the Supreme Court.

Aadhaar is a 12-digit identity number linked to a person’s fingerprints, iris scans and basic details. It is run by the Unique Identification Authority of India (UIDAI), set up in 2009. The first numbers were issued in 2010.

Scale

Over 130 crore Aadhaar numbers have been issued, covering nearly all residents, making it the world’s largest biometric ID system.

Why it was created

Many poor Indians lacked any identity document, making it hard to open bank accounts, get SIM cards or access welfare. Aadhaar aimed to give everyone a verifiable identity.

Uses

Welfare: linking beneficiaries to schemes.
Bank accounts and e-KYC.
Income tax: linking with PAN.
Authentication for services.

The privacy debate

Critics raised concerns about surveillance, data leaks and exclusion. In 2017, the Supreme Court declared privacy a fundamental right in the Puttaswamy case. In 2018, a five-judge bench upheld Aadhaar for welfare and taxes but struck down its mandatory use by private companies, such as for bank accounts and mobile SIMs (later allowed voluntarily through amended law).

Economic effects

Reduced duplicate beneficiaries.
Lowered costs of verifying customers for banks and telecom firms.
Supported digital payments.

Concerns remain

Authentication failures for manual workers or elderly people with worn fingerprints.
Data security.

The first ID

A migrant labourer who never had a birth certificate or any ID gets an Aadhaar number. With it, he opens a bank account, gets a SIM card and registers for a pension scheme.

Thinking Aadhaar is mandatory for everything

The Supreme Court limited mandatory use to welfare and tax purposes.

Key takeaways

Aadhaar is a biometric ID managed by UIDAI since 2009.
Over 130 crore numbers have been issued.
The Supreme Court upheld it for welfare and taxes in 2018 but limited private mandatory use.
It lowered verification costs but raises privacy and exclusion concerns.