Ключевые слова: air, business, chemical, chimney, china, cloud, dark, dirty, dusk, ecology, electricity, energy, environment, environmental, evening, factory, fuel, gas, global, hongkong, industrial, industry, landscape, light, modern, nature, night, oil, orange, outdoors, pipe, plant, pollution, power, refinery, silhouette, sky, smoke, station, structure, summer, sun, sundown, sunset, technology, tower, toxic, twilight, urban, warming,