 He also served as the president of many national and international conferences including the 8th "National Congress of Diseases of the Chest" (1963), the "Conference of the Association of Physicians of India" (1968), the "National Tuberculosis Conference" (1968) and the "World Congress on Asthma, Bronchitis and Allied Conditions" (1974).He was also involved with the activities of the "Tuberculosis Association of India" as a member of its various committees, and was the leader of the USAID Exchange Program of 1953 as well as the Indian Regent of American College of Chest Physicians during 1957–58 when he was entrusted with the investigation of infectious hepatitis in Delhi.Viswanathan was credited with pioneering research in bronchopulmonary diseases and was reported to be the first researcher to propose tropical eosinophilia as a distinct clinical entity in 1936.