Since I have a one-year gap due to UPSC exam preparation, can this gap be justified or covered in my study abroad application in UK for a Postgraduate?

Yes, a one-year gap for UPSC exam preparation can be justified in your UK study abroad application.

UK universities generally accept study gaps of up to five years for postgraduate applicants, especially when the time is used productively. Clearly explain your UPSC preparation in your Statement of Purpose (SOP) and include it in your CV. Highlight the skills and dedication developed during this period and how they support your academic goals.