The core subjects covered in the UPSC Civil Services Preliminary Examination include General Studies Paper I and Paper II (CSAT). Paper I covers areas such as Indian history, geography, polity, economics, general science, and current affairs. Paper II, focused on CSAT, assesses candidates in areas like comprehension, logical reasoning, and decision-making skills. Candidates should familiarize themselves with the exam pattern and syllabus to ensure targeted preparation. Mastery of these subjects enhances readiness for the mains stage and enriches overall knowledge base for public services.