The year that saw the introduction of the negative marking system in the UPSC Prelims was 2011. This system penalizes candidates for incorrect answers, affecting their overall score. For each wrong answer, a fraction of a point is deducted from the total score, thereby encouraging candidates to answer questions more cautiously. The negative marking policy aims to ensure that candidates demonstrate both knowledge and judiciousness in their responses. It's crucial for aspirants to understand this system and devise answer strategies to minimize the impact of incorrect guesses during the examination.