In OJEE counselling there are several documents which need to be submitted for the admission process. One of them is the income certificate of the parents in case isf the candidate is a total fee waiver . 

Now as you are saying that you don't have it. It will be quite hard for you to appear at the nodal centre. But you can take a undertaking for it and pray to god that the concerned authorities there don't bother about it too much. It depends on the college to college also. Some will say you to submit it later , some won't allow. But if you want to avail fee waiver then you need to submit IC. 

Hope for the best, prepare for the worst.

Thank you.