Here's your 10-point guide to why this has become a political controversy
The Aadhaar database scheme, started seven years ago by the previous Congress-led government, was set up to streamline payment of benefits and cut down on massive wastage and fraud.
Already, nearly a billion people have registered their finger prints and iris signatures. Opposition leaders and some critics say the privacy of a billion people could be compromised and agencies could misuse the data to profile and target individuals.
The opposition had accused the government of using a loophole to bypass those objections. The proposal has been presented as a financial bill, which the Rajya Sabha cannot reject. It can only return the proposal to the Lok Sabha, which is an embarrassment for the government.
So in the Rajya Sabha, opposition parties teamed to ask for changes or revisions to the bill. Because the government is in a minority in the Upper House, the amendments were approved.
But the Lok Sabha or Lower House, where the government has a powerful majority, rejected the changes.
Finance Minister Arun Jaitley has defended the legislation in parliament, saying Aadhaar saved the government an estimated $2.2 billion (around Rs.14,700 crore) in the last financial year.
He has also said a citizen's data will only be shared with security agencies on grounds of national security and with a court order.
"It has been showcased as a tool exclusively meant for disbursement of subsidies and we do not realise that it can also be used for mass surveillance,"said Tathagata Satpathy, a lawmaker from Odisha.
Raman Jit Singh Chima, global policy director at Access, an international digital rights organisation, said the proposed Indian law lacked the transparency and oversight safeguards found in Europe or the United States, which last year reformed its bulk telephone surveillance programme.
Sunil Abraham, who heads the Bengaluru-based Centre for Internet and Society, warned, "Maintaining a central database is akin to getting the keys of every house in Delhi and storing them at a central police station," he said.
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