The candidates need to score at least 75 % overall in class 12th exams with physics, chemistry and maths in their respective boards. If the candidates score more than 75% in physics, chemistry and maths but overall percentage falls below 75% ,they won't be eligible.

75% eligibility criteria is there only for admission to IITs and NITs. For all other institutions, you need to score minimum 50-60% marks . You can apply for jee mains and advanced exam if your percentage is less than 75 but you won't get admission to IITs and NITs then.