Mars usually shows off a reddish-orange sky thanks to dust scattering sunlight, but around sunrise and sunset, the area near the sun can glow blue, the exact opposite of what we see on Earth. This unusual twist happens because of Rayleigh scattering, where blue light gets scattered more than other colors, especially when the Martian air is clearer and dust levels drop. | Yup That Exists

Rayleigh density function