Hello,

As per the eligibility criteria of IES candidate need to pass  postgraduate degree in economics/applied economics/econometrics/business economics from a recognized university, the age limit is 21 years to 30 years, relaxation is provided for reserved categories, candidates in their final year are also eligible to apply on provisional basis, so yes you're eligible to appear for IES with integrated MSc Economics, check out this year official notification at https://www.upsc.gov.in/sites/default/files/Notif-IESISS-2021-Engl-070421.pdf