Dear aspirant,

70 percentile means your rank is somewhere around 400000. You will not be eligible for JEE advanced. Moreover the admission into it is not by your percentile in JEE main but from your percentile in JEE advanced. I suggest you prepare hard for the April attempt and try to secure a minimum of 90 percentile in your main to be eligible for admission in National Institute of Technology for SC candidate category and try to score a good marks in JEE advanced to be eligible for admission in IIT.

Hope this helps. Thank you.