Sale of agricultural land by poa

I want to sell some agricultural land in Mau (Uttar Pradesh). My nephew also wants to sell a part of his land for which he is willing to give the Power of Attorney to me. My question is can I sell my nephew's agricultural land using the Power of Attorney? will the registration office in Mau accept the Power of attorney prepared in Mumbai. I need to know the correct legal formalities for this sale which will take place in Uttar Pradesh.

Thanks,

Parijat