The Ga-Selati River in South Africa is being harmed by human activities, leading to pollution from various sources. A study in 2014 and 2015 looked at the river's health and how water quality affects the bugs living in it. They found that cleaner areas upstream had more diverse bugs than polluted areas downstream. The bugs were affected by things like oxygen levels and nutrients in the water. The study showed that environmental factors play a big role in where different bugs live in the river.