He continued his academic journey at the Indian Agricultural Research Institute, New Delhi, where he undertook an Associateship from 1951 to 1953.
[4] After returning to India in 1956, Rangaswami joined the Mycology Section of the Agricultural College, Coimbatore, where he continued his research in soil microbiology.
[2] There, he founded the Department of Agricultural Microbiology, the first in India to offer postgraduate and doctoral programs in the field.
[2] His research focused on plant pathogen survival in soil and microbial environments in the spermosphere, phyllosphere, and rhizosphere.
[5] During his tenure, he expanded academic initiatives and integrated plant pathology and microbiology into broader agricultural studies.
[8] He served as Chairman of the All India Sericulture Research Coordination Committee of the Central Silk Board for two terms (1973–1980).