A main source can be constituted-of-or-filled-with (air pollution).Logical formLearned from3 sentences. A (pollution problem) can be urban.Logical formLearned from3 sentences. (Auto emissions) may become a main source of (air pollution).Logical formLearned from3 sentences. Some cities may report (medium air pollution).Logical formLearned from3 sentences. (Air pollution) may be caused by automobiles.Logical formLearned from3 sentences. (Pollution indexes) can be for some major cities.Logical formLearned from3 sentences. (Sea pollution) may result from accidents.Logical formLearned from3 sentences. An (air pollution control) can be indoor.Logical formLearned from3 sentences. Pollution may exacerbate a situation.Logical formLearned from3 sentences. Some cities may have (air pollution).Logical formLearned from3 sentences. Pollution may be caused by (burning coal).Logical formLearned from3 sentences. A contributor can be to an (air pollution).Logical formLearned from3 sentences. Underground waters may undergo pollution.Logical formLearned from3 sentences. Pollution can be intensive.Logical formLearned from3 sentences. (Water pollution) may worsen.Logical formLearned from3 sentences.