Unity materials grey on distance

I am trying to generate some terrain, but the materials are greyed out when zooming out. That would look something like this:

So, what you are seeing here is the landscape I am generating, which is divided into chunks of 1616 tiles (so 1717 vertices). However, the textures of the chunks in the back, which is only 75 meters away, is not visible. How could I fix this?

I know this is an old question but as a new Unity user I just ran into this problem myself and I thought the answer might help someone else too.

In the scene window, toggle the fog to off using the drop down arrow in the menu bar at the top of the scene window.