The airlines of India were nationalized in which among the following years?

In 1953, the government nationalized the airlines via the Air Corporations Act, 1953, which gave birth to Indian Airlines and Air India. Indian Airlines came into being with the merger of eight domestic airlines to operate domestic services, while Air India International was to operate the overseas services. Furthermore, the Act gave monopoly power to Indian Airlines to operate on domestic scheduled services ruling out any other operator. Air India became the single Indian carrier to operate on international itinerary excluding some routes to the neighbouring countries which were given to Indian Airlines.