If the number of cigarettes smoked increases, then the risk for lung cancer increases.

correct. so it's TRUE. if this is a true of false question. the more you are exposed to it the more likely you will get it.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.