This study of the water quality of the Ganga was commissioned after the construction of the Tehri Dam. It acknowledges that most people in India have a belief that water from the Ganga has bactericidal properties and this might be affected by the dam. National Environmental Engineering Research Institute (NEERI) was retained by the Tehri Hydro Development Corporation Limited (THDC) to investigate any impact that the Tehri Dam might have on the water quality of the Ganga. This report presents the results of that investigation.