any transaction by way of agreement or arrangement or in any manner whatsoever, which has the effect of transferring or enabling the enjoyment of any immovable property would get the character of transfer.

2)I presume  full consideration has been received by you 

3) I presume possession is delivered to power of attorney holder .it is considered sale as receipt deed mentions consideration receipt bed by you 

4) if you sell property through POA it has to be stamped as conveyance as POA not executed in favour of blood relative 

4) better option is to sell property through registered sale deed only 

1. there will be no sale through GPA and receipt deed

2. the title will still vests with you only

3. if the buyer wants to convey the property in his wife's name in future, he will have to turn to you only, since the buyer cannot convey the property to his wife as he will not get title merely by signing GPA and receipt deed. Ofocurse he can use your GPA to register sale deed in his wife's favour. But even the GPA has to be full stamped and registered as applicable for a sale deed since the grantor and grantee of the POA are unrelated

4. so if your buyer thinks that by doing all this he can outsmart the government/revenue, he is completely wrong

1. Transfer of immovable property through GPA is Null & Void and it doesn't confer any right over the property to the buyer, as per the Hon'ble Supreme Court judgement. Hence you can't consider this as Sale and inturn can't claim capital gain/loss as in the case of registered sale deed.

2.  Any unregistered sale of property without a deed does not confer any right to the prospective buyer.

Sale will be only effected through a sale deed and its registration 

Unless and until a registered sale deed is executed by the seller in favor of the buyer, the transfer will not be complete and the buyer cannot have title to the property neither the seller can pay the capital gains tax without selling the property by a registered sale deed. 

The POA deed executed for a consideration amount would be valid and cannot be revoked, but that cannot be considered as transfer of property or transfer of title to the buyer because the power agent is not the buyer and he is a mere power agent to you. 

You should not run a risk because it will be a headache till such time the power agent is actually transferring the property in favor of any other prospective buyer by a registered sale deed, and you have to sign the sale deed or produce a life certificate at that time.

You cannot pay the capital gains tax till the property has been transferred in favor of the prospective buyer by a registered sale deed. 

- As per Supreme Court , GPA, Sale agreement , etc. are not a title documents, and it must be a registered sale deed.

- Hence, if you will sold the said  property , then the buyer will have no right to further sell the said property to anyone through a registered deed. 

- However, you can give to him a registered GPA to enter into an agreement with intending buyer , but he will have no right to enter into a registered sale deed with that buyer , as the ownership will be remained with you. 

- Hence, you cannot claim capital gains/loss on this GPA.