烟雾笼罩着城市。

___Smog hung over the city.

减少烟雾的措施对于改善空气质量至关重要。

Measures to reduce ___smog are essential for improving air quality.

工业排放极大地加剧了许多大都市区所遭受的烟雾污染。

Industrial emissions contribute significantly to the ___smog that plagues many metropolitan areas.