Ключевые слова: blue, canal, clean, danger, dirty, drain, drainage, drainage pipe, drainage site, drainpipe, drains, ecological, ecology, environment, environmental, factory, flowing, industrial, industry, lake, large, liquid, ocean, outdoor, outdoors, pipe, pipeline, plant, pollute, polluted, pollution, protection, river, sea, sewage, sewage water, sewer, sewer cleaning, sewer pipes, sewerage, stream, toxic, treatment, tube, waste, waste water, wastewater, water, water pollution,