Aadhaar is the world's largest biometric identity system with approximately 134 crore live Aadhaar holders

1. At a Glance

Aadhaar = 12-digit unique identity number issued by UIDAI (Unique Identification Authority of India) using demographic + biometric data (fingerprint, iris, face) [S1][S3].
World's largest biometric ID system with ~134 crore live Aadhaar holders and >17,000 crore authentication transactions completed [S1].
Backbone of India's Digital Public Infrastructure (DPI) — enables DBT, JAM trinity, e-KYC, subsidy delivery [S1][S3].
High UPSC salience: cuts across GS-II (governance, rights, SC judgments), GS-III (digital economy, cybersecurity) and ethics (privacy).

PIB release dated 18 March 2026 by Ministry of Electronics & IT reiterated Aadhaar scale (~134 crore holders), encryption of demographic data at rest and in transit, and that storage/processing of Aadhaar data occurs within India [S1].
Continued focus on data localisation, privacy safeguards, and authentication ecosystem expansion (OTP, biometric, face) [S1].

2009: UIDAI constituted by executive notification under Planning Commission (28 Jan 2009).
2010: First Aadhaar number issued in Maharashtra (Tembhli village, Sept 2010).
2016: Aadhaar (Targeted Delivery of Financial and Other Subsidies, Benefits and Services) Act, 2016 enacted; UIDAI given statutory status on 12 July 2016 under MeitY [S2][S3].
2017: SC in Justice K.S. Puttaswamy v. UoI declared Right to Privacy a fundamental right (Art. 21).
2018: SC (26 Sept 2018) upheld constitutional validity of Aadhaar Act; struck down mandatory linking with bank accounts and mobile; allowed mandatory link for PAN (Sec 139AA IT Act) and subsidies from Consolidated Fund of India [S4].
2019: Aadhaar and Other Laws (Amendment) Act, 2019 (Act 14 of 2019, effective 25 July 2019) — enabled voluntary use for bank/SIM via offline KYC [S2].

Implementing body: UIDAI — statutory authority under MeitY (Ministry of Electronics & IT) [S2].
Enabling Act: Aadhaar Act, 2016; amended 2019 [S2][S3].
Headquarters: New Delhi; 8 Regional Offices.
Aadhaar number: 12-digit random; issued to residents (not citizens) staying ≥182 days in preceding 12 months.
Data: Demographic (name, DOB, address, gender) + Biometric (10 fingerprints, 2 iris, photograph).
Authentication modes: OTP, biometric (fingerprint/iris/face), demographic [S1].
Live Aadhaar holders: ~134 crore [S1].
Authentication transactions: >17,000 crore cumulative [S1].
Data storage: Within India; demographic data encrypted at rest and in transit [S1].
Core biometric data: Cannot be shared with anyone for any reason (Aadhaar Regulations, 2016) [S2].

Legal / Constitutional
SC in Puttaswamy (2018) upheld Act but read down Sec 33(2), 47, 57; struck down mandatory bank/SIM linking [S4].
Aadhaar mandatory only for benefits/subsidies/services from Consolidated Fund of India [S4].
Sec 139AA Income Tax Act (Aadhaar-PAN link) upheld as not violating Art. 14 [S4].
Administrative / Governance
Enables JAM trinity (Jan Dhan–Aadhaar–Mobile) → leak-proof DBT; cumulative DBT savings reported in lakh crores.
e-KYC reduced onboarding time/cost for telecom, banking.
Scientific / Technological
Multi-modal biometric de-duplication at population scale; encryption at rest + transit; data localisation within India [S1].
Ethical / Privacy
Tensions: surveillance risk, exclusion errors in PDS authentication, biometric failures of elderly/manual labourers.
2019 amendment introduced offline verification and virtual ID to mitigate.
Economic
Backbone of DPI exports (India Stack); referenced by World Bank as a model for digital ID.

18 March 2026: PIB/MeitY communication — 134 cr live holders, >17,000 cr authentications; reaffirmed encryption + in-India storage [S1].
Continued rollout of Face Authentication as biometric mode [S1].

UIDAI is under MeitY, not Ministry of Home Affairs [S2].
UIDAI became statutory on 12 July 2016 under the Aadhaar Act, 2016 [S2].
Aadhaar Act 2016 was passed as a Money Bill (later challenged; upheld in Puttaswamy 2018) [S4].
Sec 139AA of Income Tax Act mandates Aadhaar-PAN linkage; upheld by SC [S4].
Aadhaar mandatory only for subsidies from Consolidated Fund of India [S4].
Aadhaar is issued to residents, not citizens (≥182 days in preceding 12 months).
First Aadhaar issued in 2010 in Maharashtra (Tembhli, Nandurbar).
2019 Amendment Act introduced offline KYC and Virtual ID.
Core biometric data cannot be shared with anyone (per 2016 Regulations) [S2].
>17,000 crore authentication transactions; ~134 crore live holders [S1].
Demographic data stored encrypted at rest and in transit, processed within India [S1].
Aadhaar authentication modes: OTP, fingerprint, iris, face, demographic [S1].

GS-II: Governance — e-Governance applications; Government policies for vulnerable sections; SC judgments on rights.
GS-III: Indian economy — Digital economy, DBT, cybersecurity, data protection.
GS-IV: Ethics — Privacy vs welfare delivery; informed consent.
Likely stems:
"Aadhaar has transformed welfare delivery but raises questions on privacy and exclusion. Discuss."
"Examine the impact of the Puttaswamy judgments (2017, 2018) on the Aadhaar ecosystem." [S4]
"Digital Public Infrastructure built around Aadhaar is India's most significant export-grade governance innovation. Critically evaluate." [S1]

Puttaswamy judgments (2017 & 2018) — privacy as fundamental right [S4].
Digital Personal Data Protection Act, 2023 — privacy framework around Aadhaar data.
JAM Trinity & DBT Mission — operational use of Aadhaar.
India Stack / DPI — UPI, DigiLocker, Account Aggregator built on Aadhaar.
PMJDY (Jan Dhan) — financial inclusion leg of JAM.
NPCI & AePS — Aadhaar-enabled Payment System.
Section 139AA Income Tax Act — PAN-Aadhaar linkage [S4].
Aadhaar & Other Laws (Amendment) Act, 2019 — voluntary use, offline KYC [S2].

UIDAI is under MeitY, NOT MHA or NITI Aayog [S2].
Aadhaar issued to residents, NOT citizens — confuses many.
Aadhaar Act passed in 2016, but UIDAI itself was set up in 2009 by executive order.
SC did NOT strike down the Act in entirety in 2018 — it upheld it with reading down of Sec 33(2), 47, 57 [S4].
Bank-account and mobile-SIM linkage is NOT mandatory post-2018 ruling [S4].
Storage is within India — do not confuse with cross-border cloud data [S1].

[S1] Aadhaar is the world's largest biometric identity system… — https://www.pib.gov.in/PressReleasePage.aspx?PRID=2241778 — (tier: 1) [user-supplied excerpt; live fetch returned 403]
[S2] Aadhaar (Targeted Delivery…) Act, 2016 & 2019 Amendment — https://www.indiacode.nic.in/handle/123456789/2160 ; https://www.meity.gov.in/uidai — (tier: 1)
[S3] Aadhaar: A Unique Identity For The People (PIB) — https://www.pib.gov.in/PressReleasePage.aspx?PRID=2067940 — (tier: 1)
[S4] Overview of the Legal Issues around Aadhaar (PRS) & PIB on SC judgment — https://prsindia.org/theprsblog/overview-of-the-legal-issues-around-aadhaar ; https://www.pib.gov.in/newsite/PrintRelease.aspx?relid=165553 — (tier: 1)