Is ownership necessary for capital gains??

Shweta,

If the sale was made under a power of attorney, it is as good as it being made by an agent acting for the owner. As such, the capital gains will become taxable in the hands of the owner and not of the POA holder.

Only the differential amount that is not paid by the agent to the owner will become his commission for the transaction and will be taxable as commission income and be taxable under income from business and profession.

Incase you have any further doubt, please ask

Agreed with Mr. Ankit.

He is only acting as a constituent attorney, and not as a owner of the property.