Yes, you can file RTI to obtain Copies of your Answer Sheet from Chhattisgarh Public Service Commission (CGPSC).
CGPSC was formed under the provision of Article 315 of the Constitution of India on 23/05/2001 to perform the functions of conducting examinations for appointments in the State and to advise the State Government on matters related with the State Civil Service. CGPSC is a "Public Authority" as per Section 2 (h) of the RTI Act and comes under its ambit.
You can file RTI Application asking for Certified Copies of your Answer / OMR Sheets under Section 2 (j) of the RTI Act from CGPSC by addressing the same to the designated "Public Information Officer (PIO)" and by paying the prescribed fee. You should attach a Copy of your Admit Card along with the Application and mention your Roll No., Registration No., Name of Exam on the application.
To know more about the procedure to file RTI Applications for Answer Copy, please refer https://onlinerti.com/how-to-file-rti-online-for-exam
To know more about the procedure to file RTI Applications, please refer https://onlinerti.com/
