Dear Akansha, 

If you do not have OBC - NCL Certificate, you can submit the Declaration by the Candidate in Lieu of OBC-NCL Certificate. 

The Declaration will allow you to submit the Certificate by June 5.

The Declaration is available on the second page of OBC-NCL Certificate Format available on official website of JEE Advanced. 

To know about the colleges you get, you can try Carrers 360 College Predictor 

https://engineering.careers360.com/jee-main-college-predictor