You  should make a request to the muncipal corporation . The registrar may provide a prescribed printed application form to fill. Alternatively, he/she may issue an affidavit on his/her letterhead.

2) you can also make application online at muncipal corporation website 

3) download application form 

3) upload supporting documents like school leaving certificate , ration card which reflects your name and that of parents , Aadhar card , PAN Card .passport etc 

4) make online payment and obtain receipt 

5) after scrutiny you would get the certificate 

1. Applicant has to go to the Municipal office and apply by filling up the form 10 for non availability of certificate. 
2. Applicant has to complete the form and submit along with the required documents and prescribed fees to the issuing officer.
3. Authorities will verify the details and documents to process further. Applicant will be communicated for any clarifications.
4. On the satisfactory grounds, Applicant will be notified to collect the certificate

If the above option is closed and not able to issue BC than you can apply in the court.

Form which state and city you belongs.

You have to submit an application to the concerned birth and death registrar office to issue the birth certificate of so and so. 

You may have to give the particulars and details of birth of the person whose birth certificate has been sought. 

If there's no record available in the register maintained by the authority concerned for this purpose,  they may issue non availability certificate. 

If you have other documentary evidence of birth then apply before the Magistrate. 

The question is not clear 

Which state did the birth took place?

- You should apply before the office of Birth Registrar of your zone /area for getting the birth certificate. 

- Further , you have to submit the address proof etc from the date of your birth , including the proof of your parents from the date of your birth . 

- Further, you can apply through online as well. 

In order to get NABC, you have to approach the Registrar of Births. You have to fill up a concerned form for Offline Search in their Register/Records about the details of your Birth in their Register. If no details will be found & as such, you are saying no online details are available which can validate or authenticate about your Birth Date, so in such case, after verifying your credentials & on the basis of you tendering affidavit about the random details of your Birth like Date of Birth, Place of Birth, Name of Parents, etc which are best known to you as per your knowledge, they will consider such details itself as the fact & will provide you with the NABC. 

By moving an application to the  authority under RTI Act.