4.
Go in person and sign the power of attorney in front of the consular officer, who attests it. Take your passport, the copy of your residence permit, the form, and the power of attorney with a copy. The attestation confirms only that you are the person who signed, not what the document says.
🏛️ The Indian embassy or consulate for where you live
📎 The power of attorney (original and a copy), Passport (original, and a copy of the first and last pages), Copy of your residence permit or visa, The mission's application form (miscellaneous services), with a photo
💰 Fee: As the mission's fee chart
Not confirmed: Section 33(1)(c) of the Registration Act also recognises a power of attorney executed before and authenticated by a notary public, court, judge or magistrate in the country where you live. The department's pages do not say whether such a one needs a further step such as an apostille; ask the Sub-Registrar office first.