Hello aspirant,

There is no limit for different categories of students to apply for the JEE Mains entrance exam. As per the data officially released by the authority, out of a total number of 6,19,638 candidates who registered for the JEE Main March 2021 phase, 21,787 students were from the ST category and for the JEE Main February 2021 Paper 1 there were 1,66,401 registrations and 3,216 registrations for JEE Main February 2021 Paper 2A & 2B were done from the ST category students.

Hope this helps,

All the Best!!