As telecom companies pile up a huge debt estimated to be about Rs 4.2 lakh crore amid a tariff war and a consolidation among some of the players, the Reserve Bank of India (RBI) has raised a red flag over banks' loans to them and asked the lenders to increase their standard asset provisioning more than what is prescribed so that they can build 'necessary resilience.' "The telecom sector is reporting stressed financial conditions, and presently interest coverage ratio for the sector is less than one," according to a circular issued by the central bank to the lenders. Asking the bank boards to review the telecom sector latest by June 30, the central bank said: "Consider making provisions for standard assets in this sector at higher rates so that necessary resilience is built in the balance sheets should the stress reflect on the quality of exposure to the sector at a future date."