Hello, Shrishti. You have mentioned that you belong to SC category and in JEE Advanced 2020, you had received a score of 70 marks. Well, in 2020 minimum percentage of  marks in each subject for SC Rank List is 2.50% and minimum percentage aggregate marks prescribed for inclusion in the rank list is 8.75%.

Furthermore, JEE Advanced 2020 Cut-off for CSE branch for SC candidates was 29 (for gender-neutral) and 107 (for females only).

If you want to know your chances to get admission in IIT Bombay, CSE department or any other department then check out JEE Advanced 2021 College Predictor Tool

I hope this information help you to clear your doubts

Thank you. All the best for your future!