how to remove the top and botton black bands on Nexus 5 running 5.1 with nova launcher

[jagan]

I have been running android 5.1 on my nexus 5 with nova launcher on top it. There are two black bands present on top and bottom of the screen. It is quite irritating while using some apps. How can I remove it?

Thank you

 

[Javier P]

Can you post an screenshot of that? Are you talking about the notifications and navigation bars?