Mutation of a gifted property in delhi

My grandfather gifted me a property(Pahar ganj, Central Delhi) in which we have been residing with our family since birth. My grandfather inherited it from his grandfather but there is no documented proof of inheritance or will, as it was decades ago. There is no legal heir in addition to my grandfather. The gift deed had also been registered in the office of the sub-registrar. But, the property is still in the name of my grandfather's grandfather. Means my great great grandfather. Property tax has also been filled in his name. How can the mutation of the property take place in such case. The deed was registered on 10-07-2019.