You and I are referring to completely different scores. It is true that a candidate needs to have scored a minimum percentage of around 50-60% in their high-school/intermediate board exams (so 10th/12th standard) to be allowed to sit in the selection examination.

The cutoffs I'm talking about are dependent on overall performance of all candidates. In the link I have shared this cutoff is 18% (89/480) for reserved category students. There are more details in the article about the cutoff for reserved category students being 60% of that of general category ones. There is further elaboration on how many students have to drop off because of their poor performance. These vacant seats are rarely filled.