the color of sky is blue but the wavelenght of violet and indigo is small than that of blue.then why the color of sky is blue?

Dear Jyoti,
The particles in the atmosphere are able to scatter lights of small wavelength...towards the blue part of the spectrum,
the size of the particles is not so small to scatter violet....their sizes are sufficient to scatter light at the midle last region of the spectrum,
as a result the sky appears blue.
Regards.

actually the scattered light is violet  only  but our eyes are more sensitive to blue colour therefore we see sky as bllue