The UPSC syllabus lists various subjects under headings ranging from GS-I to GS-IV. History, Geography, and Indian Society are important subjects in GS Paper 1; Indian Polity, Governance, Constitution, and International Relations are important subjects in GS Paper 2; Indian Economy, Science & Technology, Agriculture, and Environment are important subjects in GS Paper 3; and Ethics, Integrity, and Aptitude are important subjects in GS Paper 4.