Public transport flights are almost exclusively operated under IFR, as this set of rules allows flight in regions of low visibility (e.g. cloud). On the other hand, a large amount of private flying in light aircraft is done under VFR since this requires a lower level of flying skill on the part of the pilot, and meteorological conditions in which a pilot can see and avoid other aircraft. As its name suggests, SVFR is a special infrequently-used set of rules.