The real test of IAF airlift capability came in October 1962, when open warfare erupted on the Sino-lndian border. During the period 20 October to 20 November, pressure on the Service's transport and helicopter units were intense, troops and supplies having to be flown to the support of the border posts virtually around the clock and at extreme altitudes. The helicopters had to constantly run the gauntlet of Chinese small arms and anti-aircraft fire, while operating to.the tricky helipads in the mountains. Many notable feats were performed by the IAF during this conflict, including the operation of C-119Gs from airstrips 17,000 ft (5180m) above sea level in the Karakoram Himalayas, and the air-lifting by An-12Bs of two troops of AMX-13 light tanks to Chushul, in Ladakh, where the small airstrip was 15,000 ft (4570m) above sea level.
The state of emergency declared as a result of the Sino-lndian fighting resulted in disbandment of the Auxillary Air Force and absorption of its personnel and equipment by the regular IAF. An emergency training scheme was instituted in which the services of five flying clubs at Madras, Kanpur, New Delhi, Nagpur and Patiala were enlisted, more than 1,000 cadets receiving primary flying instruction with these clubs by the end of 1964. Furthermore, Vampire FBMk.52s "mothballed" since 1961, were restored to service as the equipment of newly-raised squadrons.
The IAF was expanding rapidly, its personnel strength of 28,000 officers and men at the time of the Sino-ludian conflict increasing by some two-thirds by the end of 1964, but the manpower requirements of the 33-squadron force had still to be implemented fully when the scheme was overtaken by even more ambitious expansion to a 45-squadron force which was sanctioned by the Government in October 1962, this calling for the raising of IAF personnel strength to some 100,000 by the early seventies.
Together with the arrival of successive batches of An- 12Bs from the Soviet Union and a third batch of C- 119Gs from the USA, the IAF began to receive the Canadian DHC-4 Caribou, two being presented to the Service by the Canadian Government as assistance in wake of the Sino-lndian conflict and 16 more being ordered, with deliveries commencing in September 1963, resulting in the establishment of No.33 Squadron.
An epoch-making decision was taken in August 1962 which was to profoundly alter the complexion and strength of the Indian Air Force into the decades ahead. The Government of India signed protocols with the Soviet Union for the very first supply of combat aircraft and missiles for the Indian Air Force. The purchase of 12 MiG-21 fighters from the Soviet Union - the IAF's first combat aircraft of non-western origin - and for Soviet technical assistance in setting up production facilities for the fighter in India was followed by the procurement of SA-2 (Dvina) surface-to-air missiles. Re-equipment and expansion of the IAF was now being pursued in parallel with major changes in the operational infrastructure. Prior to the Sino-Indian conflict, the IAF had been geared to provide defense against attack from the West only, but appreciation of the vulnerability of the entire Northern and Eastern border had called for profound rethinking of the operational infrastructure. It was now patently apparent that, for a country of the immensity of India, a system of purely functional Commands was impracticable and that, to cater for all potential-threats, operational command would in future, have to be exercised on a regional basis. Thus the Indian periphery was divided into three for purposes of operational control, the Western, Central and Eastern Air Commands eventually emerging. However, in order to maintain uniform standards in training and maintenance, the Training and Maintenance Commands were to remain functional.