Section 45(2) in The Naval Ceremonial, Conditions Of Service And Miscellaneous Regulations, 1964
(2)The distinguishing flags particularised in Regulation 60 shall be hoisted respectively at the fore whenever any of Indian Army, Air, Diplomatic or Consular Authorities are receiving salutes to which they may be entitled; should, however, the proper distinguishing flag not be on board the ship saluting, the blue ensign shall be hoisted. Should the ship not have a blue ensign, a white ensign may be hoisted at the fore when saluting any of the Indian authorities referred to.Section VII - Visits of Ceremony and Courtesy Calls
