Almost a seventh of China has been under heavy smog.

中国近七分之一的地区一直处于重度雾霾之下。

youdao

The sky over the city was overspread with heavy smog.

城市上空罩上了一层浓重的烟雾。

youdao

The sky over the city was overspread with a heavy smog.

城市上空罩上了一层烟雾。

《新英汉大辞典》

The heavy smog and haze that enveloped Beijing this weekend pushed the pollution index to a record high.

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His campaign believes that will strike a chord with American families, particularly in Midwest swing states suffering from heavy smog and environmental degradation.

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