How do I make a certain radius of fog dissapear?

So if you have ever played league of legends you know what a ward is right? If you don't let me tell you what happens if you place a ward in league of legends, In league of legends there is fog and when there is fog or also called fog of war you can't see the enemy but if you place a ward you can see a few radius so if a enemy enters that radius you can see them so basically all im asking is how can i remove fog in roblox after I place a item on the ground so I can spot the enemy teamate