Solved 2016 Question Paper ICSE Class 10 Physics — Question 9

Scattering is the process of absorption and then re-emission of light energy by the dust particles and air molecules present in the atmosphere.

Red colour of white light is scattered the least because wavelength of red light (λ = 8000 Å) is longest and intensity of scattered light (I) ∝ $\dfrac{1}{λ^4}$.