Fresh water, rivers and lakes are under increasing pressure due to pollution. In this workshop, students will get hands on experience in the use of Bioindicator index. After learning to identify the invertebrate species (Microscopes), students will be provided with water samples from three different locations (featuring severe to moderate pollution) then using view finder will grade the water samples. At the end of the session students will discuss and evaluate their results. Discussion will include effectiveness of bio indicator, possible sources of pollution and exploring methods to control pollution.