The key differences between the Preliminary and Mains stages of the UPSC exam lie in their structure and purpose. The Preliminary exam consists of two objective-type papers that primarily test candidates’ general knowledge and awareness of current events. Conversely, the Mains examination comprises nine papers, including descriptive-type questions that assess in-depth knowledge and understanding of various subjects. The Mains also require candidates to demonstrate analytical and writing skills through essays and case studies, focusing on their ability to articulate ideas effectively and coherently.