Why the Sky is Blue in Fine Weather?

As sunlight passing through the atmosphere it will meet the gaseous molecules and particles and thus produces scattering effect. Blue skies are produced as shorter wavelengths of the incoming sunlight (violet, blue and indigo) are strongly deflected by scattering of the small molecules of atmosphere. Longer wavelengths of red, orange and yellow light are largely unaffected they can easily pass through the atmosphere. 
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