what shall I do if my caste validity cannot be made? nor can I make ews cause I'm OBC?

Dear Yash,

Most probably you have no other option than showing them the caste certificate with month range range they want.

But please tell me one thing in comment section or in new question that what is their requirement of validity that you are not able to made it in your state? If this is the case then lot  candidates will have to suffer with this problem and i am not sure if IIT system will like this.

You must visit the authority, carrying your caste certificate that you presently have, explain him/her the situation and then he/she must understand your situation and do something.

If everything fail and you are not able to furnish the required certificate then you can carry the certificate you presently have and explain them during counselling that why you were not able to create that format, maybe they will understand it. But I strongly recommend you to somehow try to make the certificate in the validity range they are asking for so that you do not have to experience the panic during counselling time.

I hope this information helps you.

All the very best!!