Her research expertise lies in international human rights law and political theory. Her writing spans a broad range of subjects including equality and non-discrimination, minority rights (including ethnic, religious, and sexual minorities, children, women and the elderly), identity politics, theories of justice, deliberative democracy and civic participation, citizenship studies, domestic violence, and comparative law and legal transplants. Puja has been a consultant to various non-governmental organisations and is currently on the Board of Directors for Unison Hong Kong, the Asian Migrants Centre, the Association for Concern for Legal Rights of Victims of Domestic Violence and the Justice Centre.