This chapter seeks to familiarize the readers with the environmental pollution. Water is a colorless, odorless and tasteless liquid, which plays vital role in animal and human life. Nearly three-fourths of the earth’s surface is covered with water. Rainwater harvesting is the activity of direct collection or storage of rainwater into dugs, wells etc. There are two important methods for rainwater harvesting i.e. surface runoff harvesting and rooftop rainwater harvesting. Water pollution refers to contamination of water sources natural and manmade which decreases quality of water and causes degradation of water for use. Waterborne diseases, water purification, air pollution, airborne disease, noise pollution, soil pollution, marine pollution, radioactive pollution, housing and ventilation, etc. are the other important topics which are also covered throughout this chapter.