Just a weird question. Who classifies where and how big a NFZ should be? Does it come from the government? Or from DJI?

Just 2 screenshots:

Sofia

Seems ok over the Airport. But why are stadiums NFZ? And why not all of them? Near the left red circle there is another stadium that's not in the NFZ.

An Airport near Plovdiv. Not that much flights, perhaps 3-4 per day. But no NFZ?

Plovdiv

menio,
         In the USA --- jails, correction facility's , government buildings are NFZ's
Here in the U.S. I believe the government and the FAA make the classification's
FlySafe-FlyFree   

A lot of airports in Russia don't have a NFZ especially military ones. Was curious about your question too. And why is Russia under CE compliant we have a different laws concerning non licensed radio transmitters power.

Same here in Ukraine. Just stadiums that have clear venue on Google Maps covered by NFZ. Even if they have like 1 event in 2 months. It's annoying because in my city this NFZ also covers most of the park where the stadium is located. It's one of the points in the city where you can fly Mavic safely, but it's covered by NFZ much larger that stadium.