A substance or chemical that causes the contamination of the soil thereby affecting its quality and those dependent on soil (humans, animals, and plants) are called soil pollutants and the phenomenon is called soil pollution.
Scrap, fly ash, and solid wastes containing toxic chemicals and heavy metals from the industries involved in metal refining, pesticide, paper, rubber, and chemical manufacturing pollute the soil.
Domestic, urban, and commercial wastes form municipal solid waste. The majority of waste is accounted for the paper, yard, plastics, textiles, leather, and rubber waste. They can be non-biodegradable or biodegradable. On mixing with soil, they release chemicals and substances that affect the soil quality.