Abstract
58 species and infraspecies of Chlorophyta and Charophyta algae were observed in 60 samples collected in September 2017 from the Shah Alam River, Pakistan. The algal species richness and environmental variables increased down the river, except for pH. Bioindication revealed low saline, low alkaline, middle streaming, and middle oxygenated water with low to middle organic pollution with Index saprobity S 1.48-1.73, Class 2-3 of Water Quality. The trophic state was eutrophic and meso-eutrophic with increasing eutrophication down the river. River Pollution Indices RPI demonstrated increasing of pollution in the Shah Alam River in comparison with the parallel part of the Kabul River.