Hello,

Yes, if you're aiming for UPSC then you need to complete graduation in any stream from a recognized university, diploma isn't accepted in this regard there is no such restrictions of belonging to specific discipline when it comes to appearing for upsc, however if you complete your graduation in subjects like political science, public  administration, history, geography, economics, sociology etc there is considerable overlap with the syllabus of general studies and optional subjects, see if you're pursuing your degree from a recognized university say IGNOU for example then it's valid for higher studies as well as government jobs. you can definitely pursue higher studies while doing government job, if I further provide you information about IGNOU, it has various regional centres all over India, and under it are study centre where you submit your assignments, appear for term end exam etc, so there is no problem you can choose any degree of your choice, just make sure the specific degree is valid in distance mode and the university is recognized by ugc.You can apply even in the final year of graduation provisionally, and you need to attain 21 years as on 1stAugust of the appearing year.

Yes you can do degree in any subject from open university along with your job. UPSC have not specified university of qualification. So you can do your degree from an open university so that you can also work along with that. People usually do distant degree from universities along with their job. But it will be difficult for you to manage both studies and work.