On September 26th, the world’s largest biometric identification system passed a major hurdle as the Indian Supreme Court ruled that India’s Aadhaar system is constitutional, a year after it had ruled that Indians have a fundamental right to privacy. As a number of countries, including Germany, Argentina, and Spain, have implemented mandatory nationwide identification systems, India’s constitutional challenge provides some perspective on the challenges of implementing such a program on a large scale.

The World’s Largest Biometric System Explained

The Aadhaar system uses 12-digit numbers to provide residents with a digital identity linking their demographic information to biometric information such as their fingerprints and retina scans. Run by India’s Unique Identification Authority of India (UIDAI) and modeled after Social Security numbers in the United States, the program has quickly grown with 1.19 billion Indian residents enrolled. For many Indian residents, the Aadhaar number serves as the only form of identification they have, with only 200 million having a driver’s license and even fewer—65 million—having a passport.

Introduced in 2009 and retroactively legalized in 2016, the Aadhaar system was originally conceived as a way to improve efficiency in distributing public benefits by verifying citizens’ identities. However, just as the program grew in size, the scope of this identity database has similarly ballooned with Aadhaar numbers being used to track job growth and to comply with “know your customer” (KYC) requirements for new bank accounts or mobile phone lines.

With Increased Scale Comes Increased Controversy

With these expansions in enrollment and scope, the program has been steeped in controversy. Some of the country’s most vulnerable, such as the elderly, manual laborers, and patients with leprosy, were excluded from the registration process due to difficulties in the enrollment process. Other individuals who were otherwise eligible for government benefits were denied access if they did not have an Aadhaar number or did not link it with other government documents or a bank account. As the program became more widespread, additional concerns arose surrounding the security of the demographic and biometric information used for identity verification. One journalist reportedly paid an agent 500 rupees (roughly $7) for unrestricted access to the Aadhaar system’s database, providing access to information such as individuals’ names, addresses, phone numbers, and emails.

Passing Constitutional Muster

Criticism of the country’s Aadhaar system culminated as about 30 petitioners sued, alleging that the program infringed Indians’ right to privacy. In a ruling spanning over 1,400 pages, the five-judge bench disagreed four to one, finding that much of the program was constitutional.

The key question before the Court was whether the Aadhar system’s provisions were sufficiently proportional to the invasion of privacy created by the system. The Court found that the Aadhaar system’s targeted delivery of government benefits, services, and subsidies, through digital identification, enabled individuals to be secure in their right to dignity. Thus, it held that the system could be required for individuals to access public benefits and to file income taxes.

However, this treatment was not extended to other required uses of the Aadhaar system’s identity verification features. The required linking of users’ Aadhaar numbers to bank accounts and cell phone numbers was found to be a disproportionate solution to problems such as money laundering and the misuse of SIM cards, respectively. It also stated that children could not be required to provide an Aadhaar number to enroll in school or access welfare benefits.

The Road Ahead

Now that the Aadhaar system has passed its tallest hurdle to date, the challenge is far from over. Questions still loom over what the relationship between the private sector and the system will look like in the future and over how far the system will grow as more biometric information is considered. Nonetheless, the September ruling marks an important milestone, not just for India, but for the future of biometric identity programs globally.