As per the Aadhar (Targeted Delivery of Financial and Other Subsidies, Benefits and Services) Act, 2016, only a resident who has resided in India for a period or periods amounting in all to 182 or more in the 12 months immediately preceding the date of application for enrolment.
Section 139AA of the Income-tax Act, 1961 as introduced by the Finance Act, 2017 provides for mandatory quoting of Aadhar / Enrolment ID of Aadhar application form, for filing of return of income and for making an application for allotment of Permanent Account Number with effect from 1st July, 2017. It is clarified that such mandatory quoting of Aadhar or Enrolment ID shall apply only to a person who is eligible to obtain Aadhar number. As per the Aadhaar (Targeted Delivery of Financial and Other Subsidies, Benefits and Services) Act, 2016, only a resident individual is entitled to obtain Aadhaar. Resident as per the said Act means an individual who has resided in India for a period or periods amounting in all to one hundred and eighty-two days or more in the twelve months immediately preceding the date of application for enrolment. Accordingly, the requirement to quote Aadhaar as per section 139AA of the Income-tax Act shall not apply to an individual who is not a resident as per the Aadhaar Act, 2016.
If you have maintained your NRI status for the last 5 years, the income in your NRE account is free from tax. Note that tax is collected only on interest, not on the capital. You can include the information on your NRE account in your annual return, even though you do not need to pay tax on it.
No, the interest on all types of NRE accounts is tax-free.
If you buy the property on mortgage by taking housing loans, repatriation will still be possible if you pay off the loan instalments in India through your NRE account or by transferring funds from abroad.