Aadhaar's Biometric Exception Handling — UIDAI's Iris-Scan Fallback When Fingerprints Fail

Aadhaar, India's biometric digital-identity system, has enrolled more than 1.3 billion residents and underpins authentication for rations, pensions and welfare payments nationwide. Its default authentication method is fingerprint matching against the biometric record captured at enrolment.
Independent reporting documents a persistent inclusion failure in that design: fingerprints belonging to manual labourers — agricultural, construction and domestic workers — wear down with repeated physical work, and elderly citizens' prints change with age, so live scans stop matching enrolment records. The Wire reported the case of an 80-year-old woman in New Delhi who could not collect her rations for most of 2023 after her fingerprint authentication began failing in 2022. A UIDAI regional-office representative in Ranchi acknowledged to journalists that fingerprints 'do get erased or changed' with age and manual labour.
UIDAI's design response is an automatic fallback: when a fingerprint scan fails, the system prompts an iris scan instead, which is intended to let elderly citizens and labourers authenticate without a fingerprint match. This exception-handling flow is documented in citizen-facing guidance and acknowledged in UIDAI's public statements.
The fix is only partial, and it is important to say so plainly. Iris authentication itself fails for some people who have had cataract surgery, a common procedure among elderly Indians. Biometric Update reported in July 2025 that high biometric-verification failure rates were prompting renewed UIDAI scrutiny — evidence that, more than a decade after Aadhaar's rollout, authentication exclusion for exactly the populations digital inclusion is meant to serve remains a live, unresolved problem rather than a solved one.

Read the full analysis: https://www.policycircle.org/opinion/aadhaar-authentication-failures/