I'm literally shocked

I recently visited my uncle in UP, who’s in a high post at SBI. During our conversation, he casually mentioned that in some branches, officers are taking a 1% cut/bribe to pass loans. I was honestly shocked. I always thought corruption was something you hear about in government offices, not in banking, where things are supposed to be more professional and transparent. Now I’m really confused and disturbed. If this is happening in SBI (which is one of the biggest public sector banks), it makes me wonder how widespread it is. What’s the correct way to report such corruption? Are there whistleblower mechanisms in banks? How to escalate this matter to the RBI or the Central Vigilance Commission (CVC)? I never thought I’d see corruption this close in banking, and I really want to do the right thing here.