In the context of the UPSC Preliminary Exam, negative marking refers to the deduction of marks for incorrect answers. For every wrong answer, a specific fraction of a mark (often one-third) is subtracted from the total score. This system discourages random guessing and encourages candidates to answer only when they are relatively sure about their knowledge of a question. Understanding this system is crucial for strategic answering and time management during the exam, as it directly affects overall performance.