"Blue skies" refer to clear skies that appear blue due to the scattering of sunlight by the Earth's atmosphere. When sunlight enters the atmosphere, shorter blue wavelengths scatter more than other colors, making the sky look blue to our eyes. This phenomenon is most noticeable during the day when the sun is high. The color of the sky can change based on various factors, such as time of day, weather conditions, and pollution levels. During sunrise and sunset, the sky may appear red or orange due to the angle of the sun and the increased distance the light travels through the atmosphere. Sunlight, atmosphere, and pollution all play significant roles in these changes.