The differences between UPSC and state PSC exams primarily lie in their scope, syllabus, and examination pattern. UPSC, being a national-level examination, covers a broader syllabus and attracts candidates from various states, while state PSC exams focus primarily on state-specific issues and require in-depth local knowledge. UPSC exams comprise a series of stages, including prelims, mains, and interviews, whereas many state PSCs may have fewer stages. The level of competition is generally higher in UPSC due to a larger applicant pool, impacting the selection criteria and preparation strategies for candidates.