A critical review on water quality index tool: Genesis, evolution and future directions

Water quality is a substantial measure in coordinating water demand and supply. An adequate level of freshwater is eminent for biological needs and a vital side of integrated sustainable environmental development. There has been a disrupting ascend in the water pollution due to the natural and anthropogenic events. Past few years, research has enormously engrossed on the development of water quality index (WQI), as a prevalent tool for water quality assessment. This review article presented an in-depth literature-based look up of WQI's potentials concerning their use as a scientific tool for river water quality monitoring and management. This study also highlighted the importance, limitations and future directions of WQI tool to afford additional information about its usage. The review indicated the influence of the environmental features, like geographic locations and sampling periods, on the estimation of WQI. Also, WQI was projected as a single value which decreased the immense amount of water quality parameters and epitomized the data in a simple way. The incessant use of WQI tool provided long-term information for helping the water resource managers, environmental engineers and scientists in decision making and management.