Ключевые слова: background, black, chemicals, city, clean, construction, contaminated, contamination, danger, dirty, disaster, drain, drainage, dump, ecology, environment, environmental, equipment, flowing, garbage, industrial, industry, liquid, metal, natural, nature, oil, pipe, plant, pollution, production, recycling, removal, river, sanitary, sanitation, sewage, sewer, smell, smelly, stream, system, technology, toxic, treatment, tube, urban, waste, wastewater, water,