The reservation policy applies to UPSC candidates based on categories such as Scheduled Castes (SC), Scheduled Tribes (ST), Other Backward Classes (OBC), and Economically Weaker Sections (EWS). This policy is intended to promote social equity and representation in public services. Candidates from reserved categories may have a certain percentage of seats reserved or relaxations in eligibility criteria, including cut-off marks and interview scores. This fosters diversity within the civil services and aims to provide opportunities for historically marginalized groups in Indian society.