Hello Nunkesh,

First let me congratulate you on your decision to give the Civil Services Exam. Your career can only go uphill from here onwards.

For the Indian Polity section of its course you can refer -

1. Indian Polity by Laxmikanth

2. Introduction to constitution of India by Durga Das Basu

For more details of various book to refer for the exams you can follow the below link:

https://competition.careers360.com/articles/books-for-upsc-civil-services/amp

Hope this helps!

All the best with your preparation and for your exams !