Traditional Culture Encyclopedia - Weather inquiry - What does it mean that there are two circles in the city?

What does it mean that there are two circles in the city?

Haze (also known as haze) refers to a large number of dust or smoke particles floating in the air near the ground, which reduces visibility. Haze is harmful to health. Inhalation of excessive dust or cigarette dust floating in the air will damage cardiopulmonary function and may lead to death in the long run. 1952 London smog caused more than 4,000 deaths. Haze itself refers to the color of light scattered by air molecules, water vapor and dust impurities above the horizon. Therefore, it may beautify this phenomenon to call a brown-gray color that is formed by dust or cigarette dust and obstructs the line of sight "haze".