Hey there

UPSC is one of the toughest exams in india and thus students feel it hard to crack with graduation. If you are preparing for engineering it is advised to focus on engineering as the course is tough itself. Also in interview they may ask regarding your engineering discipline and may check as if you completed engineering sincerely or not as they judge your personality on that basis. you can do GK, easily with studies and if you can steal time from your engineering then can go for polity, history and others too.

good luck