Ключевые слова: air, clean, cleanup, clear, clouds, colorful, colors, conduit, construction, contrast, corroded, corrosion, dam, drain, environment, environmentalist, flowing, greenpeace, gushing, industrial, industry, natural, oil, old, opec, opposite, pipe, pipeline, polluter, pollution, pump, rust, rusty, sewage, sewer, sky, stream, treatment, tube, waste, water, waterfall, waterpipe,