Dr. Sethi is Senior Fellow, Centre for Air Power Studies, New Delhi and heads its Nuclear Security project. She is also Fellow, International Relations, Centre de Sciences Humaines, New Delhi. On the research faculty of Institute for Defence Studies and Analyses, New Delhi, from 1997 to 2001, she focussed on nuclear energy proliferation, export controls, and disarmament.
She completed her Ph.D from School of International Studies, JNU, New Delhi in 1997. Between 2002 and 2005 she carried out a Research Project for the Department of Atomic Energy on Nuclear Energy for India's Energy Security at the Centre for Strategic and International Studies, New Delhi.
She is the author of Argentina's Nuclear Policy and co-author of Nuclear Deterrence and Diplomacy and has written a number of academic articles in national and international journals. She contributes regularly to national and international dailies and is visiting lecturer at several training establishments of the Indian armed forces.