"Three Financial Years" from the year it is generated.

Look at the DoPT circulars, Ministry of Personnel, Public Grievances and Pensions ( No 13 - Validity period of OBC Certificate in respect of creamy layer status of the candidates) -  https://doptcirculars.nic.in/Default.aspx?URL=c1SoiFnAQNeH%20

File No. 36036/2/2013-Estt. (Res-I) dated March 31, 2016 https://documents.doptcirculars.nic.in/D2/D02adm/36036_2_2013-Estt.Res-I-31032016.pdf

Hi,

Yes, you will have to renew your OBC non creamy layer certificate. It is obvious that your certificate has expired. The validity of the OBC certificate Non Creamy Layer is usuallyfor one year. OBC certificate has to be renewed each year. You can renew the certificate by applying for it at the district office of one's city or districts. With suitable documents like,obc certificate, validity,non creamy layer,I'd proof,address proof,etc, you can go to district office and renew it. Some state provide online facilities also.

Hello Dear Student,

You need to Renew your OBC NCL (Non creamy layer) Certificate.

Validity of OBC (NCL) Certificate issued by Central Government is One year.

There are two types of OBC (NCL) Certificate:

1. Issued by Central Government.
2. Issued by State Governments.

*Generally the validity of OBC NCL Certificate for Central Government is 1 Year and Whereas Validity of OBC NCL Certificate for State Government is 3 years.

You need to renew Both.

For Renewal:
You should go to a stamp vendor in your District or Tehsil court along with your old OBC certificate and requisite Documents. You can apply from Tehsil court or District Court, The Tehsildar or Magistrate will issue your renewed OBC NCL Certificate.
Online facilities are also available in Some states like in Uttar Pradesh "Lokvani Kendra's" are available for these services.

All the Best!