Hello Aman,

Well there is no specific eligibility criteria for SC in CSAB Special Round. In CSAB  Special Round they only ask that the candidate should have valid JEE Main rank and should meet the JoSAA eligbility criteria. Now there is no specific JoSAA eligibility criteria. Those appearing for JoSAA should satisfy the eligibility criteria of the participating institutes. Like if someone want to get NITs, then he/she has to satisfy the JEE Mains eligibility criteria as per his/her category. 

I have mentioned below the eligibility criteria for CSAB Special Round counselling : 

• Candidates should have a valid JEE Main rank 2019 and must meet up the JoSAA eligibility criteria.
• The candidates who didn't participated or registered in JoSAA are also eligible to apply for the special round.
• The candidates who have failed to get a seat in JoSAA after participation will also be eligible for special round.
• Candidates who got seats in JoSAA but failed to report to the allotted institute or had withdrawn their participation from counselling can also apply for special roun.
• Those candidates who didn't opted for special round counselling after JoSAA will not be eligible to apply for CSAB Special Round.

You can go through this link and checkout the details regarding CSAB counselling : https://engineering.careers360.com/articles/csab

Hope this helps you. Good Luck !!!

Hello Aman, looks like you are about get into NIT or IIIT so congratulation for that. And as per your question the minimum marks in 12th standard to become eligible to get seat in NIT is 65% for sc/st candidate and for general category student it is 75%. Goodluck.