Hi Somya,

I think you will be eligible to applyfor UPSC examination.

Although only a diploma certificate would not have let you sit for the exam, but since you do have mentioned about graduating and that too (I hope) from a recognized university, I do not think you will face any problem while applying.

As per the eligibility criteria, the applicants must have a degree of any University or other  educational institutions established by an Act of Parliament or declared to be deemed as a University.

Also I have researched to some extent to find that, the Candidates who have a (technical/professional) educational qualifications as equivalent to ( technical/professional) degree which are recognised by the Indian Government would also be eligible for admission to the CSE examination.

Hope this helps!