This study investigates effects of surface water quality of Upper Ganga river basin. The current study uses a general categorization system, viz. excellent, acceptable, slightly polluted, polluted and heavily polluted water for the quality assessment of surface water. Considering the Indian scenario, Indian Standards and CPCB have defined the concentration ranges for these classes. Further, water quality parameters, viz. hardness CaCO₃, biological oxygen demand (BOD), fluoride (F), dissolved oxygen% (DO%) and pH, were studied in basins for the pre-, post- and monsoon time periods. The numerical equations to convert the actual concentration values into pollution indices were used. On the basis of individual index data, an ‘Overall Index of Pollution’ (OIP) is calculated. The OIP is calculated at Uttarkashi and Rishikesh stations on Upper Ganga river basin using observed water quality data. Water quality degradation has occurred in the basin; consequently, the health status of the river has changed from acceptable to polluted.