One major grouping of hallucinogens typically allows the user to remain in some touch with the real world and to remember much of what he or she experienced. this group of drugs was referred to as

The correct answer is "Phantastica".

Explanation:

"Phantastica" is a term that was used to describe the effects that certain drugs have on the body, that seem to create a world of fantasy in people's mind. The word "Phantastica" honor the title of a book with the same name published by Louis Lewin that describes a series of psychoactive plants. Nowadays, "Phantastica" is the name of a major grouping of hallucinogens that create a world of fantasy while the user remain in some touch with the real world. This group include peyote, psilocybin and LSD drugs.

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.