The Corruption Clusters and Corruption Fragments are a direct result of the Cube Queen's arrival on the Fortnite island. Destroying these clusters are a part of the new Dark Jonesy questline.
There are three Corruption Clusters that are spread out on the map and you need to destroy any two of them in order to finish up this mission.
Where to Destroy Corruption Clusters in Fortnite
As mentioned before, there are three specific locations where you can find Corruption Clusters in Fortnite. These three locations are marked on the map below.
In order to complete this challenge, all you need to do is destroy any two clusters and you will get a nice little XP boost. To make things easier, these Corruption Clusters are located close to the Convergence itself.
That being said, once you've made your way to these Corruption Clusters, all you need to do is start swinging your pickaxe at them till they are destroyed.
Completing this mission is as easy as it gets.
This mission will only be accessible to you once you've recovered the Spirit Vessel. So make sure you complete that before you try to destroy these Corruption Clusters.