Rivers are critical to human life because they are strategically significant in the world, providing primary water supplies for various purposes. Rivers are the prime importance of any country as most of the cities are settled near the river. Due to developmental activities and increase in population, it will result in huge waste generation. Surface water quality is affected because of increasing urbanization and industrialization. The aim of this research is to examine the effect of climate change and industrialization on the water quality of the Sabarmati river using a mathematical model. For this study, four important towns along the lower Sabarmati River have been considered and water quality data was considered from 2005 to 2015. In this study, different water quality parameters were considered to derive a water quality model. Results show the water quality downstream after Ahmedabad city is worse compared to the other location where the Maximum WQI is 0.71 at Rasikapur and average WQI is 0.50 for the same location for the last 15 years. It has been observed that the effect of the monsoon and also by comparing time scale water quality model the role of regulations for industrialization also plays an important role in the quality of Sabarmati river. HIGHLIGHTS Water quality modelling by using fuzzy logic approach for Sabarmati river.; Calculate and analyze the WQI for Sabarmati River for the last 15-year time period.; Analyze the impact of climate change and industrialization on river water quality.; Comparison of the WQI mathematical model for the Sabarmati river.; Analysis of self purification capacity of river using strength of Sabarmati river.;