Protest can be against pollution.Logical formLearned from8 sentences. A decrease can be in (pollution levels).Logical formLearned from8 sentences. A reduction can be in environmental pollution.Logical formLearned from8 sentences. Cars may cause pollution.Logical formLearned from8 sentences. Pollution can be in a US-city.Logical formLearned from8 sentences. A (pollution control equipment) can be required.Logical formLearned from8 sentences. (Air pollution) can be at levels.Logical formLearned from8 sentences. (Pollution problems) may pertain-to a city.Logical formLearned from8 sentences. A form can be constituted-of-or-filled-with visual pollution.Logical formLearned from8 sentences. A battle can be against pollution.Logical formLearned from8 sentences. Problems may be caused by pollution.Logical formLearned from8 sentences. Pollution can be in a continent.Logical formLearned from8 sentences. Pollution may be generated by (power plants).Logical formLearned from8 sentences. (Coal burning) can be a source of pollution.Logical formLearned from8 sentences. Pollution can be from a middle.Logical formLearned from8 sentences.