Reserve Bank of India (RBI) Governor Urjit Patel should own up moral responsibility for the massive $1.8 billion scam/fraud allegedly committed by diamond retailer Nirav Modi and resign his post, demanded a top banking employees union leader."The continued silence of RBI Governor with regard to the scam/fraud in PNB is surprising and astounding. It indicates the deep involvement and failure of RBI in non-monitoring the Nostro account of PNB," C.H.Venkatachalam, General Secretary, All India Bank Employees' Association (AIBEA) told IANS.According to him, the fraud-hit Brady branch of PNB is a Category A foreign exchange bank branch and the RBI failed to monitor it resulting in the massive scam/fraud."The RBI Governor should own up moral responsibility for the gross failure and resign," Venkatachalam said.According to him, the RBI has its nominees on the PNB's Board of Directors. Further the RBI conducts inspections at all bank branches and hence the central bank cannot escape responsibility.Venkatachalam also demanded revamping of RBI, adding that Prompt Corrective Action should be taken on the central bank.