Pollution: Definition & Types | Air, water & Soil Pollution

Human beings are organisms who try to manipulate the environment to fulfill their needs and comforts. Pollution is a result of such manipulation and degradation of the environment by humans for their personal gains. The increase in human population and great advancement in industry and technology has disturbed the delicately balanced and healthy environment.

Have you ever wondered what pollution is?

Pollution Definition: It is an undesirable change in the physical, chemical, or biological characteristics of the air, water, and soil making them harmful for living organisms is termed Pollution. The agents or substances that pollute the environment are called pollutants

Pollution is majorly categorized into:

1. Air pollution
2. Water pollution
3. Soil pollution

Let us discuss the various effects of all the 3 major types of pollution that are harming our environment.

Air Pollution

Air Pollution

The release of harmful pollutants into the air is called air pollution. There is an increase in toxic gases such as carbon dioxide, sulfide, nitrogen oxide, hydrogen in the air which is reducing the air quality day by day. Most breathing or respiratory problems are arising due to air pollution. You might have seen the corrosion on monuments and several buildings, it is due to air pollutants that come down on earth in the form of acid rain. Smoke, dust, sulfur dioxide, nitrogen dioxide are examples of suspended particulate matter (SPM) which are some of the major air pollutants.

Both manmade and natural pollutants contribute to air pollution or air contamination. Volcanic eruptions, dust storms, forest fires are examples of natural sources of air pollution whereas gases emitting from automobiles, industries, garbage burning are examples of manmade causes of air pollution.

What is Acid Rain?

Acid Rain

The Sulphur dioxide and the oxide of nitrogen released from industries and from burning of fossil fuels, when dissolved in rain results in acid rain.

This acid rain increases the acidity of the soil, thereby affecting fertility of soil, plants and animals

It also increases the acidity of the water bodies thereby affecting aquatic life.

It also corrodes metals, painted surfaces, slate, stone and marbles.

Depletion of the Ozone layer: We all know that the ozone layer is the shield that does not allow the UV rays from the sun to reach Earth’s atmosphere. Chlorofluorocarbons (CFCs) used in refrigerators, air conditioners, fire extinguishers, aerosol sprayers, etc destroy the ozone layer in the atmosphere. The depleted ozone layer allows more ultraviolet radiations to pass through it which then strikes the earth. These radiations have a very harmful effect on living organisms.

These radiations can cause skin cancer, damage to eyes\damage to immune system, increased embryonic mortality in animals and humans.

Harmful Effects of Air Pollution

Respiratory problems: When one inhales the suspended particulate and gaseous pollutants such as sulphur dioxide and nitrogen dioxide along with the air, it causes bronchitis, asthma and lung cancer.

Similarly, inhalation of polluted air containing dust, cement dust, asbestos dust, pollens etc. may cause sneezing, allergy and tuberculosis.

Carbon monoxide poisoning-

Carbon monoxide emitted from motor vehicles and cigarette smoke, when inhaled combines with hemoglobin to form a very poisonous compound called carboxyhemoglobin.

It drastically reduces the availability of oxygen to the body tissues and leads to suffocation and finally death.

Water Pollution

The release of harmful pollutants into the water is called air pollution. Water pollution or water contamination refers to the increase in harmful substances in rivers, seas, oceans, lakes, aquifers, groundwater, or other water bodies. The degradation in water quality is affecting the animals, humans and all biodiversity.

When the concentration of toxic substances such as the wedge, toxic metals, chemicals, oil, grease, radioactive substances, industrial and agricultural waste increases in a water body, the water becomes toxic and poses all types of health risks to our environment. The release of untreated water in our water bodies is damaging the environment from the core.

Water pollution

Harmful Effects of Water Pollution

Man is the main cause of water pollution. Water pollution is the cause of many harmful effects.

Human diseases

The addition of undesirable substances such as- sewage, industrial wastes, agricultural wastes and household wastes adds many viruses, bacteria, protozoa and harmful metals like mercury etc. to the water bodies. This causes diseases like typhoid, cholera, dysentery, jaundice and hepatitis etc.

Destruction of useful microorganisms-

When untreated industrial waste gets mixed with water in rivers and lakes etc. the acids and alkalis present in the industrial wastes adversely affect the useful organisms present in the water bodies.

As these microorganisms are the natural cleansing agents of water, therefore, self purification process is hindered in their water bodies

Soil Pollution

The release of harmful pollutants into the soil is called soil pollution. Soil pollution or soil contamination is caused when there is an increase in harmful substances, such as chemicals in soil.

The major causes of soil pollution are industrial activity, excessive use of chemicals or fertilizers, herbicides, and manure. Infiltration of radioactive substances such as radium, uranium, thorium, and nitrogen can make the soil toxic.

Soil can become highly toxic if the concentration of heavy metals such as lead, arsenic and mercury increases. Soil contamination poses health risks for plants, animals and environment as well.

Soil pollution

Harmful Effects of Soil Pollution

Huge heaps of solid wastes make surroundings dirty and the decomposition of waste spreads the foul smell. These heaps of waste become breeding places for carriers of diseases. Solid waste blocks the drains and this becomes the breeding site of mosquitoes etc. Soil pollution by chemicals due to dumping of industrial waste or acid rain or fertilizers and pesticides reduces the fertility of the soil and hence reduces the crop yield.

Soil Erosion

The removal and the transportation of the top layer of soil from its original position to another place with the help of certain agents such as strong winds and fast running rain water is called soil erosion. The soil is left with no humus thus loses its fertility.

To prevent the soil erosion, intensive cropping should be done. If the fields remain covered with crops throughout the year, top soil will not be exposed to winds or rain. Thus, no soil erosion will occur.


Presence of sewage and fertilizers in polluted water provide a lot of nutrients to the algae present in the water bodies and excessive growth of algae takes place. The process is called Eutrophication.

The algae subsequently die and aerobic decomposers become active. They rapidly consume the dissolved oxygen of the water and decompose these dead algae. All the oxygen is used up and thus in the absence of dissolved oxygen, all the aquatic organisms are adversely affected.

A change in temperature-

Aquatic organisms are used to a certain range of temperature in the water body. Some industries use water for cooling in various operations and later return the hot water to water bodies bringing the change in the temperature of the water of the water bodies

Also the water released from dams is colder than the water at the surface, which also brings changes in the temperature

This sudden marked change in the temperature of the water-bodies will be dangerous for the aquatic animals and affect their breeding. The eggs and larvae of various animals are particularly susceptible to temperature changes.

Global Warming (Greenhouse effect)

Global Warming

The level of carbon dioxide, methane, and oxides of nitrogen is increasing in the atmosphere. These are called greenhouse gases. These gases trap the infrared radiations reflected by the earth. This heats up the atmosphere of the earth which is termed as global warming.


Smog is a dark fog formed by condensation of water vapors, dust, smoke particles and various gaseous pollutants such as oxides of nitrogen, sulphur dioxide, hydrogen sulphide etc. This smog reduces visibility leading to accidents and also causes many respiratory problems.

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