Critical thinking skills necessary for the UPSC Civil Services exam include the ability to analyze complex situations, evaluate evidence, and develop rational arguments. Candidates need to synthesize information from diverse sources and apply it to real-world scenarios. Problem-solving skills are essential, as aspirants must tackle case studies and policy-related questions effectively. Additionally, the capacity to question assumptions and think creatively is vital for navigating unpredictable scenarios. Clear communication and articulation of one's thoughts are necessary, enabling candidates to convey their reasoning convincingly in both written and oral formats.