Na for property in surat city, gujarat

I am one of the flat holder out of 32 flat apartment. It is located in final T.P. no. 9 of Surat Municipal Corporation. The said property was constructed before 1995 but in those days builder had intentionally not cleared the NA process of the said apartment and sold all the flats to different buyers. Now our society which is not a registered society wants to make our titles clear so kindly guide the process for getting NA certificate & getting our names on City survey registrar.