Why does the sky change color?

The reason the sky turns yellow is due to sandstorms.

During sandstorms, the atmosphere is filled with large dust particles. At this time, the scattering characteristics of sunlight are mainly non-selective scattering, that is, scattering that occurs when the size of the scattering particles is much larger than the wavelength. The scattering intensity has nothing to do with the wavelength. Large particle dust causes non-selective scattering to dominate, and the sky no longer appears blue due to Rayleigh scattering, but instead takes on the color of dust—earthy yellow.

Definition:

A sandstorm refers to a weather phenomenon in which strong winds blow up dust and sand on the ground, making the air very turbid and with horizontal visibility less than 1km. Sandstorm is a weather phenomenon in wind-eroded desertification. Its formation is affected by both natural factors and human activity factors.

Natural factors include strong winds, reduced precipitation and its sand sources. Human activity factors refer to the increase in the frequency of sandstorms caused by human damage to vegetation during the process of economic development.