Environmental pollution is, in simple terms, an undesirable change that occurs in our natural surroundings—the air we breathe, the water we drink, and the soil that grows our food. It happens when harmful substances or forms of energy are introduced into the environment, disrupting the delicate balance of our ecosystems.

The National Academy of Science in the USA provided a formal definition in 1966 that remains highly relevant today:

An undesirable change in physical, chemical, and biological characteristics of water, air, and soil that may harmfully affect human, animal, and plant life, industrial progress, living conditions and cultural assets.

Any substance, form of energy, or action that causes this imbalance is known as a pollutant. These pollutants can interfere with the natural processes of an ecosystem and cause damage to living organisms. They can be broadly categorized into two main types based on their origin:

• Natural Pollutants: These pollutants originate from natural forces and events. While they are not caused by human activity, they can still have a significant impact on the environment. Common examples include ash and gases from a volcanic eruption or smoke from a large forest fire.
• Man-made Pollutants: These pollutants are the result of human activities. The release of excess gases or matter from our daily lives and industries falls into this category. A clear example is the excess carbon monoxide released by the ever-increasing number of automobiles on our roads.

Now that we understand what pollution is, let’s explore the four major forms it takes in our world.