Dear aspirant,

UPSC interview is not to test your knowledge but your personality and your honesty. It's ok if you don't give the answers of 9 out of 10 question there, but the thing that matters is that how you will take that pressure of not able to answering those questions.

So, they will not judge you at all if you will give the geniune answer of their questions and show them your honesty. Just tell them truth and the reasons behind your 4 years gap. They will not judge you at all.

Thank you! All the best!