From 1959-61 India added 150,000 men & 8 additional fighting brigades to its army, citing Chinese Threat. Before 1962 Sino-India war, India had 45 brigades. Deployed 42 of these against Pakistan & only 3 against China & lost the war. Over 80% Indian Army is still facing Pakistan.
After Indian Army’s humiliating defeat at the hands of Chinese in 1962, USA & Western countries provided financian support & arms/equipment to Indian Armed Forces. This helped India to raise its defence spending from 600 million in 1961-62 to over 1700 million in 1963-64.
Pakistan had inherited a much smaller force (one-fourth of Indian strength) which could not conceivably pose a threat to India. India was thus faced with no external threat. Yet, immediately after the independence, India started expanding its armed forces.