Mandatory elements of general power of attorney

If the GPA is given for the purpose of immovable property then the entire details of all the properties are to be mentioned in the deed.

If not then it will be valid only to the extent of the properties mentioned therein.

A General Power of Attorney can be prepared authorizing the son to handle and manage all properties pertaining to the individual, though the details in regard to some of them are unknown. However, for the known properties, such as the fully owned flat and the one where he is a legal heir, more details should be included. The GPA can be generalized to apply over any property, whether wholly or partly owned by the individual. A generalized GPA is not per se invalid for Indian law allows a GPA to encompass general powers to all present and future properties owned by the grantor. However, upon registry, the sub-registrar may insist on some sort of identification of properties for clarity. If the particulars are not known, then a general clause will suffice. The GPA would then state that the GPA covers all the present and future properties over which the person has rights or claims.

Basis of a GPA: Grantor's and attorney's particulars.
The nature of powers being granted.
All known properties are a general clause with respect to unknown ones.
Signed and attested; and, if the individual is abroad, then attestation by the Indian Embassy.
Thus, it's not necessary that all the information of every property should be incorporated for the GPA valid to be signed; however, adding a general clause is preferable to have wider coverage.

Thank you very much Sankalp Sir for your reply, it is really useful and in detail. 

Coming to the point of attestation of POA by Indian Consultate, in some of the countries there is a long queue and delay in getting appointments and a bit bureaucratic practices by government employees and time consuming.

Therefore as India is a part of Haque Convention, what if the POA is notarised by an overseas notary and thereafter Haque Apostille taken on the POA.  This process may seem a bit costly in terms of fees charged by overseas notary and apostille additional cost as compare to consulate attestation which is much cheaper but hectic.

This service of going through Haque Apostille is very convienent, hasle free and fast. Some of the Notaries do provide premium and express service like a one stop shop and makes transaction very smooth and convienent.

Also there some NRI service provider and advocates who are suggesting to have Apostille instead of Consulate for those who can afford and do not want to wait long, they are also confirming documents such as POA/Will, Gift Deed, Affidavit bearing Apostille will be accepted for registration.

Hence instead of consulate attestation if the document bears Haque Apostille, will it be accepted for Registration at Registrar of Assurance office. - Please if it can be reconfirmed.

Yes, as India is a signatory to the Hague Apostille Convention, an overseas notary having notarized a General Power of Attorney can be apostilled for use in India. The Apostille process makes it faster and simpler for documents between nations of the same convention to authenticate without the attestation of a consulate. From a cost point of view, consulate attestation is usually less expensive, though it may take quite some time and at times also involve a bureaucratic delay. Apostilled documents are a bit more costly, but they are quicker and hassle-free. In fact, many NRIs have successfully registered property documents with the apostille, but then again depending on the jurisdiction, local Registrar offices in India may still insist on consulate attestation as it would be much easier for them to verify. So, the answer is to contact the Registrar of Assurances where the GPA will be registered and confirm that apostilled documents are acceptable.

Thank you once again for your advise, will check with the Registrar before registration. :)