How can I protect myself from fake FIR?

Sir , I am a student. I prepare for government job exams. But an FIR has been lodged against me by a friend of mine. The investigating officer has somehow made one-sided allegations against me. For which there is no evidence. I was called to the police station by the investigating officer. I answered the questions asked correctly and then returned home as per his orders. I did not receive any letter or order again. Then when I applied for my passport, I came to know that a case was pending against me. we prepare for government job examination. Due to this, we may have to face a lot of problems in our future. Please help me and give proper advice.