pollution in wide area

例句：

1. 1. The factory has been heavily polluting the air with its exhaust fumes.
   这家工厂排放的废气严重污染了空气。
2. 2. The river is severely polluted due to the industrial waste.
   由于工业废物，这条河流严重污染。
3. 3. The government has taken steps to reduce pollution in the city.
   政府已经采取措施减少城市污染。