As per reports, RBL bank has written off a loan of Rs. 300 Crore within 7 months from the sanction of the loan. This seems to be a major reason for the sudden intervention of RBI. 

RBI has appointed its person on the board of the lender as an additional director. The stock tumbled by 20% after that action. 

Today, the stock is trading low by around 8%. The stock is also under the F&O ban for today.