Light of shorter wavelengths
Scattering is the process by which small particles and gas molecules in the atmosphere diffuse part of radiation in all directions. Scattering occurs when radiation waves hit gas molecules or particles of dust and are not absorbed by them
Shorter the wavelength, higher the Scattering
Particles or molecules, much smaller than the wavelength of light(0.5micro metre),produce a Scattering of sunlight that is inversely proportional to the fourth power of the wavelength. This means shorter wavelength scattered much more than longer wavelength.