This presents the results of the first-ever work on chemical composition of the street dusts of Guwahati. The dusts were characterized with respect to pH, electrical conductivity, texture, Cation Exchange Capacity, content of exchangeable cations Na, K, Ca, Mg and total contents of the metals, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sn, V and Zn. The work on road dust characterization was supplemented with an analysis of the road run-off, evaluation of the ecotoxicity of the metals in it, estimation of the metal uptake by roadside plants, and also evaluation of the heavy metals associated with suspended particulate matter (SPM) in ambient air. The work correlated the different results with one another. An elaborate description of the background to the work and the methodology were followed with separation of the chemical phases by sequential extraction and evaluation of the bioavailability of Cd, Co, Cr, Cu,Fe, Mn, Ni, Pb, and Zn. Pb and Zn followed by Mn, Ni, Co and Cr were found to be mostly associated with the bioavailable fractions in the street dusts of Guwahati, India.