Hello,

The beauty about UPSC exam is it allows candidates from all background to appear for the exam, hence there is no discrimination amongst candidates, they need to be passed or appearing in the final year of graduation and be 21 years old, it doesn't matter you come from which background as long as you are able to strategize well, that's all matters, what happens in the case of people not belonging to humanities is they have to restart everything from the basics and this is fine there are various candidates from different walk of life who succeed in this exam, and you too can if you can understand what are the demands of the exam, as it's such an extensive syllabus you have to know what to read and what to skip, but yes if I talk about optional paper in Mains then it has engineering subjects of electrical, mechanical and civil,  so candidates from these backgrounds if they choose the same subject then it becomes easy for preparing the optional paper.