Hello Sumit,

In UPSC syllabus there is 26 subjects. In Mains exam candidates is to choose one option subject from the UPSC list of 26 subjects. Each optional subject has 2 papers of 250 marks.

And UPSC prelims subject list

1.History

2.Geography

3.Political Science

4.General Science- physics, chemistry & biology

5.Environmental Science

6.Sociology

I hope the information was helpful for you. Good luck.