The maximum age limit for candidates appearing in the UPSC Civil Services Examination varies based on category. Generally, the limit for the General category is 32 years, while for OBC candidates, it is 35 years, and for SC/ST candidates, it is 37 years. Additionally, certain government services allow age relaxation for ex-servicemen and candidates with disabilities. It's crucial for aspirants to check official notifications for any updates or changes regarding age limits and eligibility criteria specific to the examination.