We have a PAN-system which was used for all financial transactions, including things like company registrations, tax filings, bank accounts, loans etc.
Now, you must link your Aadhaar with your:
- PAN, before you can file a tax or register a company
- Bank Account, or else it could be shut down (this was pushed down the parliament via a amendment to the prevention of money laundering act)
Most countries have varying KYC-norms. However, Aadhaar is a very-weak KYC-source. It doesn't require proof of citizenship (foreigners can get aadhaar) or residence (you are required to stay for 180 days in India, but UIDAI doesn't verify this). It doesn't verify proof of residence either (it was meant as a identity document for everyone - even those without homes). Add this to the fact that UIDAI has fired half of the agencies on grounds of fraud who were responsible for Enrollment.
There are a lot more issues with Aadhaar: there is a no proper security procedure, no audit reports have been published ever, and despite the numerous breaches, UIDAI refuses to take a proper stance.