(Air pollution) can be in a continent.Logical formLearned from12 sentences. Pollution can be nocturnal.Logical formLearned from12 sentences. Pollution may decline.Logical formLearned from12 sentences. Pollution may be increased.Logical formLearned from12 sentences. Pollution can be from a continent.Logical formLearned from12 sentences. An (air pollution) may pertain-to a state.Logical formLearned from12 sentences. (Air pollution) can be in a state.Logical formLearned from12 sentences. A kind may undergo pollution.Logical formLearned from12 sentences. Pollution can be gaseous.Logical formLearned from12 sentences. (Pollution problems) can be chronic.Logical formLearned from12 sentences. Pollution can be deliberate.Logical formLearned from12 sentences. Pollution may reach a person.Logical formLearned from12 sentences. Pollution may grow.Logical formLearned from12 sentences. Global warming may be caused by pollution.Logical formLearned from12 sentences. A (pollution index) may pertain-to a world-city.Logical formLearned from12 sentences.