If you execute POA in favour of mother in law it would attract higher stamp duty 

Hence execute POA in favour of close family member only like your parents or siblings 

Dear Sir

1. Power of attorney can be given to blood relative also. Infact it can be given to any person who is competent. POA, can be given to blood relatives or non-blood-relatives, - BUT - should be an Indian citizen AND SHOULD NECESSARILY BE LEGALLY CAPABLE AS DEFINED UNDER THE CONTRACT ACT.

Thank You!

A GPA for to sale  immovable property can be given any relative or friend. There is no such restriction on relative. GPA attested by Indian Consulate has to be validated by District Registrar by paying certain validation charges. If a GPA is given to non blood relative, you have to pay slightly higher charges for validation. That is only the obligation.

1. If the POA is given to a blood relative, the stamp duty will be nominal. However if you give POA to your mother-in-law, then you have to pay 2.5% of Market rate of the property towards stamp duty.

2. To avoid it's adviced to appoint a POA, who is a blood relative.

That is a totally false statement based upon a wrong knowledge of the law.

PoA can be given to ANYONE.

Incorrect

the POA is just required to be stamped for 50% market value of the plot as in most states when a POA is given to a non-blood relative, then such POA is required to be fully stamped and compulsorily registered

in order to avoid the above, a mere Presentation POA to the MIL should suffice without any power to sell

the sale deed whenever made can be signed by you and your wife before the Indian Embassy/Consulate and then couriered to your MIL who can then present the signed sale deed before the concerned Sub-Registrar of Assurances for complying with the registration formalities on your and your wife's behalf 

No there is no such requirements you can give poa to non relatives too. If you need any further assistance then you can approach me through kaanoon or LinkedIn.

1. The property is held jointly by you and your wife and she is the blood relative of your wife.

2. Ordinarily no single person can be blood relative of both the husband and wife of a Hindu Couple.

3. Moreover, both of you are staying abroad and can not come to India for which you have executed the said POA in favour of your MIL.

4. The said POA is perfectly valid for the purpose of registering the sale deed for and on your behalf.

You have been properly advised about this,  however she may be permitted to act as your power agent too provided she pays additional stamp duty which is applicable for non blood relatives. 

- Since the said plot is jointly owned by you and your wife , then being the blood related to your wife her mother is authorized to sell the property on behalf of you both.