PM2.5 concentrations were measured in residential indoor environment in slums of central India during 2012–2013. In addition, a suite of chemical components including metals (Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Pb, Mo, Se, Sb, Na, Mg, K and Hg), ions (Na+, Mg2+, K+, Ca2+, F−, Cl−, NH4+, NO3− and SO42−) and carbon (OC and EC) were analyzed for all samples. Indoor PM2.5 concentrations were found to be several folds higher than the 24-h national ambient air quality standard (60 µg/m3) for PM2.5 in India, and the concentrations were found to vary from season to season.