A Refresher on Buying Plots Under Tamil Nadu Housing Board (TNHB) Scheme The Tamil Nadu Housing Board, or the TNHB, is a state government agency that is responsible for constructing affordable housing. It has become a fundamental element of Tamil Nadu's urban development over the years, and addresses multiple income groups, like the Economically Weaker Sections (EWS), Low Income Group (LIG), and Middle-Income Group (MIG) and High-Income Group (HIG).