✔ 最佳答案
This situtation only happen in Hong kong.It is the geogical location in Hong Kong.
As in summer, there is onshore wind from the sea that blow the pollotants away.
But in winter, there is offshore wind from the north og Hong kong(Mainland China),
the pollutants mostly comes from the Industrail area from China.As we all know, there is not much factories.The pollutants are blow from the China.
Is this okay?