In case the account holders are unable to furnish details and provide self-certification by the new deadline, banks and financial institutions have the option of blocking the accounts.
Once the details are furnished they can operate the accounts. The provision applies to accounts which come under the ambit of FATCA regulations.
Banks and financial institutions were asked to obtain self-certification and carry out due diligence for all individual and entity accounts opened from July 1, 2014 to August 31, 2015 to comply with the Foreign Account Tax Compliance Act (FATCA) pact signed by India and the United States.
In July 2015, India and the US signed a tax information sharing agreement under a new US law, FATCA, aimed at bolstering efforts for automatic exchange of financial information between the two nations about tax evaders.
"The account holders may be informed that, in case self-certifications are not provided till April 30, 2017, the accounts would be blocked, which would mean that the financial institution would prohibit the account holder from effecting any transaction with respect to such accounts," the tax department said in a statement.
Tax officials said that the accounts would include banks, insurance, stocks. Account holders will also have to mention their Aadhaar numbers.