Bile produced in the liver is stored in the before entering the intestine.

The answer to this question is the gallbladder. The gallbladder is a small organ under the liver that stores bile that came from the liver. The gallbladder functions as a tool to transfer the bile that is used to break-up the fatty foods in the small intestines and it also function to drain waste.    

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.