Pollution is the introduction of substances or energy into the natural environment at a rate faster than they can be dispersed, diluted, decomposed, recycled, or stored harmlessly. Pollutants can be foreign contaminants (solid, liquid, or gas) or waste products of human activity such as pesticides and industrial chemicals.

The most common type of pollution is air pollution which affects people globally, especially in low and middle income countries. Air pollutants, mostly fine particulate matter (PM2.5 and PM10) from fossil fuel combustion in households (kerosene, wood, animal dung and crop waste), road transport and industrial processes, are linked to strokes, heart diseases, lung cancer, respiratory illnesses, and premature death. Children and adolescents are particularly vulnerable to the impact of air pollution due to their developing organs and immature immune systems.

Water pollution is also an ongoing problem with many rivers and lakes contaminated by industrial and agricultural pollutants. Some signs of pollution can include changes in the color or clarity of a water source, odors and decreased wildlife sightings. Keeping soil healthy can also help protect water quality as pollutants can be washed from the land and into waterways.

Pollution impacts everyone, but the poorest and most marginalized communities are more affected by it. This is a major impediment to achieving health, well-being, and the Sustainable Development Goal of leaving no one behind.