See, BITS Pilani (All the campuses at Pilani, Goa and Hyderabad) only consider the admission of those people through the board marks scheme who have topped their respective boards exams.

For example if there are two persons, on is the 1st rank of CBSE board and the second is 2nd ranker in the same boards, then BITS will only offer the admission to the first person. If you are the topper of board, you can easily apply at BITS. All the best!