Find the album you want to delete in the right side panel and click on the trashcan next to its title. You will be asked to confirm deletion of the album.
If you're viewing the album on a separate tab you can also click on the trashcan icon next to the album's title.
Users with access to the album will no longer be able to open it and view its contents, and the album itself will be permanently purged after 72 hours. In that time frame it is still possible to recover the album.
Note: Deleting an album does not delete the assets in the album.