What is scattering of light? And on what factors does the scattering depend?

(N/A) Scattering of light is the phenomenon in which light rays deviate from their straight path upon striking particles present in the atmosphere.
As sunlight travels through the Earth's atmosphere, it gets scattered by atmospheric particles. Light of shorter wavelengths is scattered much more than light of longer wavelengths.
The amount of scattering is inversely proportional to the fourth power of the wavelength $(\lambda)$. This is known as Rayleigh scattering, given by the relation: $I \propto \frac{1}{\lambda^4}$.
Hence, the bluish colour predominates in a clear sky since blue has a shorter wavelength than red and is scattered much more strongly.
The scattering depends on the relative size of the wavelength of light $(\lambda)$ and the size of the scatterer $(a)$:
$1$. For $a << \lambda$, Rayleigh scattering occurs, which is proportional to $\frac{1}{\lambda^4}$.
$2$. For $a >> \lambda$, it is called geometric scattering.
$3$. For $a \approx \lambda$, it is called Mie scattering.