Industrial waste includes waste produced by factories, mills, and mines that can be hazardous or non-hazardous. It is categorized as liquid waste, sludge, solid waste, or hazardous waste. In Malaysia, industrial waste has evolved over time with the country's major industries - starting with chemical, textile, and metal working in the 1970s, expanding to include food/beverages, furniture, and plastics in the 1980s, and now focusing on electronics, engineering, and telecommunications. The amount of industrial waste generated is directly related to the level of industrial production.