To be eligible for NITs, the candidate must have secured at least 75% aggregate marks in Class 12. 5% relaxation in marks for Sc, St and pwd candidates.Or the candidates should be within top 20 percentile of their respective Class 12 boards. So You are in Top 20 percentile of your board, this makes you eligible for admisson to NITs. Subjects considered to calculate these marks are - PCM, a language with highest score, another subject other than these four where you have got highest marks. But this year it's different. As all the subjects of class 12 of several boards have not conducted and marks have been provided on the basis of internal assessment and previous exam marks, many students have affected by these. So CSAB has decided to withdraw this criterion of 75% marks in 12th. Now for this year i.e. Jee Main 2020, candidates only need to show the passing certificate of class 12 and have to qualify Jee Main for admission to NITs and other centrally funded Institutes. So for this year, if you have 12th score less than 75%, it won't create any problem for getting NITs. You have to qualify Jee Main with a valid score to be eligible for counselling.