Hello aspirant

LSR BA(hons) Political Science  is the better option over DTU Mechanical engineering for a civil service aspirant as you can choose Political science(PSIR) as your optional and it is a very scoring subject in comparison to Mechanical engineering as optional also political science as a subject will help you in GS as well as prelims whereas mechanical engineering wont. You will find so many aspirants in your class and well as in your college as DU is hub for civil services aspirants .

Hope this helps.