Page 59 - Health & Physical edu- 8

materials. Therefore, we should reduce the production of non-degradable waste
materials.

2. Re-using Method

Using the same means and resources time and again is called re-using method. Using
the same non- decaying but reusable materials several times after cleaning them
well helps to minimize the production of solid waste and reduces environmental
pollution.

3. Recycling Method

If we cannot reuse the same materials after they become useless, other goods can
be produced through the same. This process is known as recycling method. This also
reduces the production of solid waste and helps control environmental pollution.
Old and useless papers, plastic goods, goods made up of metals, etc. can be brought
into use through recycling method.

Need and Importance of the Air

Living beings cannot survive without air. Plants and animals need oxygen for their
respiration. The oxygen in the air reaches the lungs through respiration and is
carried to the cells by the blood through the blood circulation process. When the
cells get oxygen, they produce energy.This energy enables humans and animals to
walk or do various physical activities. Due to the regular supply of oxygen in it, our
brain works well.

The Causes of Air Pollution

The decrease in the quality of the air due to the mixture of biological and non
-biological substances as a result of natural and human activities is called air
pollution. The major causes of air pollution are as follows:

a. Mixing up of dust, dirt and sand in the air due to blowing wind or storm

b. Mixing up of the natural gases in the air which are produced from beneath

the surface of the earth

c. When the smoke produced from the industries, factories and vehicles is
mixed in the air

Health & Physical Education, Class-8 55