The distinction between Prelims and Mains in UPSC lies primarily in their formats and objectives. The Prelims, comprising objective-type questions, aims to filter candidates based on general knowledge and current affairs. In contrast, Mains entails subjective papers where candidates provide detailed written answers, reflecting analytical and critical thinking skills across various subjects. Additionally, success in Prelims is mandatory to qualify for Mains, which ultimately affects overall selection. Mains also carries weightage for assessing candidates’ preparedness for the Civil Services.