Waste is defined as unwanted or useless materials that are disposed of. The Basel Convention provides definitions of waste and disposal. Waste comes in solid and liquid forms from various sources like households, commerce, and industry. Improper waste management can negatively impact human health through chemical poisoning, increased disease, and toxicity. It can also affect the environment by polluting water sources and harming aquatic life. The key to reducing these impacts is following the waste hierarchy of reducing, reusing, and recycling to minimize waste generation and ensure proper disposal.