If your query is devoid of actual facts or backgrounds details you will certainly get a misguiding opinion only.
In your first question you said that "" This sale deed was between GDA and my mother.
3. My mother paid the stamp duty, registration fee and free hold fee to GDA and the sale deed was registered with sub-registrar. ""
This implies that your mother was the absolute owner of the property hence after her demise, the property will automatically devolve on all her legal heirs.
Whereas In your subsequent question you say that ""Till now GDA authorities are saying since your mother wan as power of attorney holder, after her demise, the sale deed has no value. Her powers can't be passed on to legal heirs. The actual owner is Mr.Yadav and land belongs to him. What you are saying is completely different, that my mother was absolute owner. ""
Now you decide that which one of the above questions is correct.
If your mother was only a GPA holder of Yadav, upon her death the GPA deed becomes infructuous.
Do you have the copy of the registered sale deed on your mother's name, if so, you can apply to the revenue authorities to transfer or mutate the properties on the name ofthe legal heirs of the deceased owner, if they refuse, ask them to give it in writing after which you can decide the further course of legal action as envisaged in the law for the purpose.