Which book I refer to crack IIT mains
You can start your preparation by the help of NCERT books it will help you to clear your basics and to build your concepts strong.
After that you can recommeded below books for your preparation
Physics
- Concepts of Physics by H. C. Verma
- Fundamentals of Physics by Halliday, Resnick and Walker
- Problems in General Physics by I. E. Irodo
Mathematics
- Hall and Knight
- S.L. Loney
Chemistry
- Morrison and Boyd for Organic Chemistry
- J. D. Lee for Inorganic Chemistry
- Modern Approach to Chemical Calculations by RC Mukherjee
All the best for your preparation!!