The subjects included in the UPSC Civil Services Mains Examination typically consist of nine papers. These include the qualifying language papers, two General Studies papers, one essay paper, and optional subject papers. The General Studies papers cover a range of topics such as Indian polity, history, geography, and ethics, while the optional subjects allow candidates to choose based on their preferences and expertise. This diverse structure ensures a comprehensive evaluation of candidates' knowledge and analytical skills essential for effective civil governance.