Urbanites live in a disgusting polluted atmosphere of their own making and the pollution that the urbanites poison themselves with reduces the urbanites' natural cognitive function.

>In 2016, researchers at Harvard and Syracuse University found that human cognitive function declined by about 15 percent when indoor CO2 reached 945 parts per million, and crashed by 50 percent when indoor CO2 reached 1,400 parts per million

Urban zones have CO2 levels roughly 200% greater than the rest of the planet and CO2 causes reduced cognitive function in all urbanites.

https://www.theatlantic.com/science/archive/2019/12/carbon-dioxide-pollution-making-people-dumber-heres-what-we-know/603826/