After his return to India, he worked at the Delhi University from 1934 to 1961 in various capacities as reader, professor and Head of the Department of Physics. He was scientific advisor to
Ministry of Defence from 1948 to 1961 and was then appointed as chairman of the
University Grants Commission in 1961 where he worked till 1973. Dr. D S Kothari (Padma Bushan & Padma Vibhushan), Scientific Advisor to Ministry of Defence, Govt. of India is an Outstanding Physicist, Educationalist and considered as the Architect of Defence Science in India. Founder of most of the DRDO labs in India i.e. Naval Dockyard Laboratory (later renamed Naval Chemical and Metallurgical Laboratory), Mumbai, Indian Naval Physical Laboratory, Kochi, Centre for Fire Research, Delhi, Solid State Physics Laboratory, Delhi, Defence Food Research Laboratory, Mysore, Defence Institute of Physiology and Allied Sciences, Chennai, Directorate of Psychological Research, New Delhi, Defence Electronics and Research Laboratory, Hyderabad, Scientific Evaluation Group, Delhi, Technical Ballistic Research Laboratory, Chandigarh. D S Kothari Played a crucial role in setting up of UGC and NCERT. Dr. D S Kothari and Dr. P Blackett worked together in Cavendish Laboratory, Cambridge University under the guidance of Lord Ernst Rutherford, the Father of Nuclear physics, later together they paved the defence education system in India. == Achievements and honours ==