The subjects included in the UPSC Prelims encompass two papers. The first paper focuses on General Studies, covering topics such as current events, history, geography, polity, economy, environmental ecology, and general science. The second paper is the CSAT (Civil Services Aptitude Test), assessing candidates' comprehension skills, logical reasoning, and analytical skills. Both papers are objective-type and play a crucial role in screening candidates for the Mains examination. Mastery of these subjects is essential for success in progressing through the UPSC selection process.