In 1979, the RBI classified money stock in India in the following four categories:
M1 = Currency with the public, i.e. coins and currency notes + demand deposits of the public known as narrow money
M2 = M1 + Post office saving deposits
M3 = M1 + Time deposits of the pubic with banks called broad money
M4 = M3 + Total post office deposits (excluding National Saving Certificates)