Hard Air (1132) is the second most populous Carillon world after
Carillon itself. It is a large planet with a thick atmosphere,
reaching 50 atm pressure at sea level. Most of the population live in
floating cities, hovering in the region where the pressure is
approximately that of Carillon. Most of these cities rely on gas bag
systems for lift, but recently, several grav cities have been built
and appear to work quite well.