The syllabus for the UPSC prelims exam primarily consists of two papers: General Studies Paper I and General Studies Paper II (CSAT). Paper I covers topics like Current Affairs, History, Geography, and Indian Polity, focusing on a broad understanding of these subjects. Paper II tests candidates on their reasoning ability, comprehension, and numerical aptitude, ensuring they possess the requisite skills for civil service. Mastery of these subjects is crucial, as performance in these prelims determines eligibility for the mains examination.