The eligibility criteria regarding age for the UPSC Civil Services Examination stipulate that candidates must be between the ages of 21 and 32 years for most categories. However, there are age relaxations for certain groups: candidates from the Scheduled Castes and Scheduled Tribes can apply up to 37 years, and those in the Other Backward Classes can apply until 35 years. Additionally, there are provisions for candidates with disabilities, which allow further extensions based on specific criteria. Understanding these age limits is essential for prospective candidates as they prepare for this competitive examination.