MUMBAI, May 27 (Xinhua) — India's central bank on Friday said it will be opting for a "graded approach" towards introducing its digital currency. In its annual report released on Friday, the Reserve Bank of India said that the design of the central digital coin needed to be in line with the objectives of its monetary policy, financial stability and efficient operations of currency and payment systems. "The Reserve Bank proposes to adopt a graded approach to introduction of Central Bank Digital Currency (CBDC), going step by step through stages of Proof of Concept, pilots and the launch," the annual…