How to avoid transparency behind the volumetric world shader? I have a volumetric shader set up for the World. 



But when I render, I see a transparent background behind where the density is too low. 



Is there a way to remove transparency and add a background color or texture instead?
Check in "Render Properties > Film" and make sure Transparent is unchecked.



If you want to add a background color, but not have it affect the lighting of the scene you can hookup "Camera Ray" from the Light Path node to a mix shader.