A contaminant is any substance that makes an environment unclean or unsafe. This can include chemicals, waste products, or biological agents that pollute air, water, or soil. Common examples of contaminants are heavy metals, pesticides, and plastic waste, which can harm ecosystems and human health. Pollution occurs when these contaminants are introduced into natural resources, disrupting their balance. For instance, air pollution from vehicle emissions can lead to respiratory problems, while water pollution from industrial runoff can affect aquatic life. Reducing contaminants is essential for maintaining a healthy environment and ensuring the well-being of all living organisms.