polg: Pollution Generation
Variable
Global
Pollution Generation []
polg = p * clip ( poln , poln1 , swt6 ,time)* polcm

polg in the updating graph: ( how to read )
In nodes
p : population
polcm : pollution-from-capital multiplier
poln : pollution normal (pollution units/person/year)
poln1 : pollution normal no. 1 (pollution units/person/year)
swt6 : switch time no. 6 for poln (years)
Out nodes
pol : pollution