It talk about water pollution in general

1. Water Pollution
Grade: 7
Instructor: Zinah ALHarthi

2.  As the grow of Earth's population is continues,
 people are ever-increasing the stress on the water
resources around the planet. That leads
oceans, rivers, and other inland waters to being
"squeezed" by human.
 so the water quality is reduced.
 (reducing the water quality means) water pollution.
Introduction:

3.  Definition 1:
 "Water pollution" is defined
as the addition of harmful or
objectionable material that
leads to reduce water quality.
What is water pollution

4.  Definition 2:
 Water pollution defined as that, when one or more
substances have add to water to reach certain extent
which cause problems for all living things in our
planet.