What does a persistent colorful glow hanging in the sky long after sunset suggest about the atmosphere?

Answer

It strongly suggests the presence of fine, suspended particles like dust or pollution

A prolonged glow, even as the sky darkens elsewhere, indicates that fine, suspended particles (aerosols) are present. These particles efficiently scatter visible light across the spectrum, holding onto the illumination longer than pure air molecules can.

What does a persistent colorful glow hanging in the sky long after sunset suggest about the atmosphere?
lightskyatmospheresunsettwilight