The significance of the 73rd and 74th Constitutional Amendments in UPSC lies in their role in empowering local governance. These amendments established a framework for panchayati raj institutions and urban local bodies, ensuring decentralized governance and participation in decision-making. They also emphasize the role of women and marginalized groups in local governance, promoting inclusivity. Understanding these amendments is crucial for grasping India's political structure and for answering questions on constitutional provisions and local governance in the exam. Their implications on effective governance and community development are significant.