Blue is the color of the sky. It is the color of the infinite, since objects seen from a great distance seem to be blue. It is the color of the balance of the energies. The total absence of light is Black. White is the color of light as it comes from the Sun. White can be decomposed in many of the colors of the spectrum when a prism deflects it. White is considered the sum of all the color of the spectrum. Black is considered the absence of light and the absence of any color. A rainbow is the best example of the white light of the sun being decomposed by the tiny drops of water floating in the atmosphere into the many colors of the spectrum. It is one of the most beautiful effects of the physics of color.
Why is the sky blue?
Short answer: Because is Blue!. 🙂
Long Answer: When the total darkness (Black) of the unquantifiable space of the cosmos mixes with the blinding (White) light of the sun, that combination produces the Blue of the sky. In nature colors (made of light) mix in a different way to the colors in an artists palette (which are made of solid grounded pigments). No wonder white and black produces gray or bluish gray in a palette.
The symbol of Yin and Yang reflects the two opposite forces trying to balance, that is why is painted in black and white. Blue is the representation of those two opposite forces in a perfect mix. No wonder blue is the favorite color to represent the skin color of many Indian deities.
Every color in nature has its own value and need. But blue is the color of greatness. Even the vast ocean seems blue under the blue sky when there is good weather.
If somebody says that blue has any negative connotation, that person needs to enlighten his dark mind with the light of knowledge and wisdom.
The Creator has given the maximum of blue to nature: Sky, rivers, ocean, lakes.
Best Wishes and Happy White and Blue Christmas and New Year