In Zavachim 88b it states that the robe atoned for loshon hara spoken in public.............A question can be asked , why was the robe completely blue? What's the connection between blue and loshon hara?
Perhapes the answer is as follows:

Rabbenu Bachya in parshat Shoftim (introduction) relates that-------"it is known that heaven was created first and called "shamayim" because fire and water which are opposites combined together to form the heaven which could only be done if both fire and water made peace with one another" (end of quote).......

The color of the sky is blue to remind us of peace, as is the robe (meil). It is obvious that a person that pursues peace will never speak Loshon Hara (gossip) ,as loshon hara can only cause strife among people........If water and fire can make peace to form the sky in order to perform the will of G-d, man can as well........

The color of sky blue epitimizes the attribute of peace that should be actively pursued by all.....Perhapes a good start in the prevention of loshon hara is the pursuit of peace....Let us all find methods and ways to properly pursue peace, and thus become better people......Have a good Shabbos