Change line EmpireDistanceScale - increase number and the distance factor becomes more severe
TooManyCitiesThreshold - decrease to make conquest harder, because your empire will become progressively unhappier as it exceed this number
TooManyCitiesCoefficient - increase, as this will give you a higher unhappiness penalty as you exceed TooManyCitiesThreshold
WarDiscontentMaxUnits - decrease, and the larger your army is outside of the city radius the unhappier your civ will be
WarDiscontentPerUnit - increase and your penalty will be higher as you exceed WarDiscontentMaxUnits
Here are some more
MaxMartialLawUnits - decrease, and you get less benefit from martial law
MartialLawEffect - decrease, and you get less benefit from martial law
Alter your city improvement effects for Happiness-type improvements. For instance, reduce the benefits of an arena to only give +1 happiness. Go into Buildings.txt. Same with wonders...
Go to const.txt and change
to make unhappy at 75 and revolt at 70
Go to DiffDB.txt and change
to 75 to reflect the global unhappiness change that you made in cons.txt, or cities will be rioting as soon as you build them. Distance factors, war discontent and other unhappiness penalties take a turn to kick in on newly-built cities.
And here is one by using the pollution settings, but you will need to do all of the following...
Lower the threashold at which pop pollution starts from 16 to 6, located in the DiffDB.txt
To offset some unwanted side-effects of more pollution in the game, double the amount of pollution necessary to cause a global disaster. It is in the pollution.txt
Lower the crime offset by 5, so that you will not have a higher crime rate because of the lower happiness levels. Crime offset is the happiness level below which you have a 1 percent increase in crime for each number. It is in the govern.txt.
LOCAL_POLLUTION_CHANCE - located in cons.txt.
Lower the possibility of getting a dead tile to offset the increased production in the game. Change setting to LOCAL_POLLUTION_CHANCE 0.0002
POLLUTION_POPULATION_RATION - located in DiffDB.txt
Rasie the amount of pollution generated by each pop from 15 to 20.
Currently, I have a city at size 11 generating -2 unhappiness from pollution with above settings.