Natural water bodies and their water quality is swiftly deteriorating due to various natural and anthropogenic activities and different types of emancipations arising from populace growth, rapid increase in urbanization and industrialization. Zooplankton community assists as pollution level indicator in any aquatic ecosystem because the zooplankton species rapidly responded to environmental changes. The habitat ecological parameters and diversity of the zooplankton inhibiting in the upper Ganges catchment basin and its main tributaries were studied for the period of two years (September 2018 to September 2020). In total, 8 sampling stations was identified to assess the impact of anthropogenic influences on zooplankton diversity using analytical index assessment tools. With the three indices, i.e. WQI (Water Quality Index), NPI (Nemerow’s Pollution Index) and OIP (Overall Index of Pollution), the influence of several anthropogenic events on the quality of water was assessed. Four groups of zooplankton including Cladocera (5 genera) Copepoda (4 genera) Protozoa (3 genera) and Rotifera (3 genera) were recorded in the selected sampling stations. Cladocera was dominating in sampling station 7 and 8, whereas Copepoda was dominating group at sampling station 1, 4, 5, 6, 7 and 8, followed by Rotifera which was dominating group at sampling station 2 and 4 while Protozoa was dominating group at sampling station 4, 6 and 7. Few habitat ecological parameters, i.e. turbidity, DO and BOD, exhibited a minor upsurge in sampling station 7 and station 8. © The Author(s), under exclusive licence to The National Academy of Sciences, India 2024.