New Delhi (CNN)India's Supreme Court has voted to uphold the legality of the country's controversial Aadhaar program, the world's largest biometric database which contains the personal details of an estimated 1.2 billion Indian citizens.
Aadhaar: India Supreme Court upholds controversial biometric database
In a 4:1 verdict Wednesday, the five-judge bench ruled that the scheme does not violate the right to privacy, a key element in a long running case challenging its constitutional validity.
The 1,400 page ruling, however, did introduce new restrictions on how Aadhaar information could be used, including measures preventing corporate bodies from demanding data.
Under the ruling, Aadhaar details will no longer be mandatory for opening bank accounts, obtaining mobile phone sim cards or enrolling children in schools.
The ruling will continue to permit the government to request Aadhaar information for tax reasons.
"We see it as a big victory of the Modi government," said Sambit Patra, spokesman for Prime Minister Narendra Modi's Bharatiya Janata Party (BJP).
"The Supreme Court has upheld the constitutional validity of Aadhaar, and has also said that it does not violate privacy," he added.
The massive centralized database was initially launched in 2009, when the now main opposition Congress party was in power, as a voluntary program to help prevent benefit fraud.
Since then, Modi and his BJP-led government have championed its growth resulting in a significant expansion in both its usage and application.
More than 90% of the entire Indian population is now registered in the identity program, which sees citizens issued with a 12-digit number that correlates with specific biometric data such as iris scans and fingerprints.
Though the system is voluntary, participation is required in order to access a range of key welfare and social services, making opting out all but impossible for most Indians.
The program in theory meant banks and government agencies could instantly verify people's identities, but it triggered concerns over the invasion of privacy and fears that Aadhaar could be used as a mass surveillance tool by the state.
Several new security measures were introduced to the database in January this year, after an alleged security breach in which an Indian journalist was able to buy access to citizens' personal details from anonymous traders for as little as $8.