According to RBI maximum study loan for education in domestic country is Rs.10 lakhs and for studying abroad, it is Rs.20 lakhs. Loan taken up to Rs.4 lakhs is allowed without collateral security and when the loan amount exceeds, there is rule to have collateral and a third party guarantee which is most cases is the parents of the student. Collateral is necessary for the banks to be on the safer side. 

Though there can be some considerations for exceeding the limit for collateral security and that depends completely on the banks.

You can approach standardized banks for their respective procedure.