As far as most of the IITs are concerned, Scheduled Caste and Scheduled Tribe Category studemts are by defauly given remission in tuition fee. For General, OBC and other EWS Category students there is provision of Merit cum Means Scholarships, provided income is below 5 lakhs, you get remission in total and tuition fee. In some IITs there is also a provision of stipend besides scholarship, however your performance in institute is considered.

Hello.  It totally depends on the income certificate and the eligibilities set by the colleges. If you have income less than 1 lakh, then a full fee reimbursement is possible. So please do check at the official website for the complete information.

Hope that helps!