Dear Rahul, according to the official website, the canfifate should possess Post-Graduate degree in Economics or Applied Economics or Econometric or Business Economics from a recognised University. So with your qualification, you are eligible to appear for IES exam. For more information, please visit their official page at: http://www.ies.gov.in/ies-aspirants.php

Dear aspirant, 

Hope you are doing well. As per your query and according to the eligibility criteria of Indian economics service you have to have a post graduate degree in economics / applied economics /business economics from a recognized university. It doesn't necessarily matter what you have done for your bachelor's degree. So yes you will be eligible to appear for the exam. Hope you find this helpful. Thank you.