^Sun appears red at Sun rise & sun set

^Sun appears red at Sun rise & sun set

This is because at Sun rise & sun set light passes through greater thickness of atmosphere, as a result more scattering takes place & blue colour & low wavelengths are scattered away by the scattering caused by the atmosphere & the colour which reaches us is unscattered red.

General scattering

When size of obstacles encountered by the light is much greater than the wavelength of light used, all wavelengths of light are scattered equally.