How to merge Calendar into one?

I sync my calendars and contacts on windows with Outlook, and after syncing with iCloud it's doubled all my calendars.

how can I fix this? it's not a big deal because I still have original calendar on the phone. Any recommendations how to prevent this would help.

and the most important I noticed that I have two calendars "Calendar" and "home" is there anyway to merge them? so I would have only one calendar?
Maybe this can be done inside of iCloud?

Thanks in advance.