The sky seems blue due to

Rayleigh scattering.The blue colour of the sky is due to Rayleigh scattering. Little of the red, orange & yellow light is affected by the air. As light moves through the atmosphere, most of the longer wavelengths pass straight through. However, much of the shorter wavelength light is absorbed by the gas molecules. The absorbed blue light is then radiated in different directions. It gets scattered all around the sky.