Are vacancies filled based on the availability of qualified candidates in each subject for Master Cadre positions?

I’m Harjit From Patiala  particularly interested in understanding the recruitment process for Master Cadre positions. Could you provide insights into whether vacancies for Master Cadre positions are filled based on the availability of qualified candidates in each subject? If so, how is this process typically carried out, and are there any specific criteria or considerations that influence the allocation of candidates to different subjects?