Can I negotiate the interest rate a bank has charged on my loan?

Your primary reference point is the loan agreement you signed — if the interest rate charged genuinely matches what's specified in that agreement, there's generally limited legal basis to dispute it purely on the grounds that you now feel it's too high, since you agreed to those specific terms at the outset.

However, if there's a genuine discrepancy between what was verbally represented to you at the time of taking the loan and what the actual signed agreement states, or if charges were applied that weren't properly disclosed or agreed to (hidden fees, undisclosed penal charges), you may have grounds to challenge those specific discrepancies through the bank's grievance mechanism, the Banking Ombudsman, or a consumer complaint.

Regulatory guidelines do require banks to disclose interest rates and charges transparently, so it's worth carefully reviewing your loan agreement and any sanction letter against what you were actually charged, to identify any specific, provable discrepancy before pursuing this further with a lawyer's help.