Affidavit

I am a 1978 born and I don’t posses a Birth Certificate. Till now, my Matriculation Marks sheet and certificate (having my DOB written in them) is working fine with all the places… I have domicile of my native state, BIHAR. I went to get a Nationality Certificate from Tehsildar Office in Mumbai, Maharashtra. They are insisting me to get my Birth Certificate as it will have my place of Birth written on them. They are not recognizing a Sworn Affidavit which generally people submit for getting Indian Passport.

It may be noted that some states are not issuing a Nationality Certificate. Why? BIHAR is one of them..

If Govt. of India is recognizing a sworn Affidavit for those born before 1989, why the Maharashtra State Tehsildar’s Office is not recognizing that? Is a “sworn affidavit on Non – Judicial Stamp Paper and duly stamped” legally valid and binding in all Central and State Government Offices or not?

What legal validity this Affidavit have? Kindly Explain