Life zone
From Wookieepedia, the Star Wars wiki.
The life zone was the region of upper atmosphere on oxygenated gas giants such as Bespin, Kril'dor or Taloraan that was of the proper pressure and temperature to support oxygen-breathing lifeforms such as Humans.
On Bespin, the zone was a 30 kilometer band located 150 kilometers inside the outer edge of Bespin's atmosphere.
