The No.1 Op Group (also referred to as Opl and Operational) nomenclature was used between 1947 to 1980 on four occasions for three different commands. At the time of independence, there was the No 1 Operational Group which controlled all the flying Unitss including the flying training Unitss. On 22nd July 1949 the No 1 Operational Group was redesignated as the Operational Command which later on became Western Air Command (WAC). The reorganisation of IAF led to the formation of No 1 Operational Group again at Calcutta on 27 May 1958. This group was responsible for the operations of the IAF in the eastern as well as the central sector of the country. The No 1 Operational Group was upgraded to Eastern Air Command on 1 Dec 1959 at Calcutta. In the wake of the Chinese threat No 1 Operational Group was re-established at Tezpur on 8 Oct 1962 giving it control of assets in the NEFA. In June 1963, this Opl group moved to Shillong and got redesignated as the new Eastern Air Command (The command in Calcutta being renamed as CAC). Subsequently, No 1 Op Group was re-established at Jodhpur on 21 Sep 1972, it was rechristened as the South Western Air Command on 23 Jul 1980