Once upon a time there lived a big tribe in a city called Haining. They had to live indoors most of the time owing to the thick haze outside. The haze contained a lot of tinny particles which were harmful to their health. However, they had to go out occasionally to make a living, wearing masks, of course. 

Their cars moved like snails with the lights on. Even if they walked, they had to go very slowly with their ears cocked, for they could hear the sounds but couldn't see the face of another person. Traffic accidents were common. It was harder for elders to walk about. Oddly enough, if they fell on the way, no one dared help, for they might accuse you that it was you who knocked them over. 

What was more curious was that they never reflected on the causes of the thick haze. They did whatever they could to make money without considering whether it would pollute the environment or not. Many farms were transformed into factories or companies. They got richer and richer, and more and more families bought cars and other fancy toys, which produced a lot of gasoline fumes. Many peculiar diseases which were never heard of or seen began to appear. But they remained calm and took it easy as they always did. 

Consequently, they lived a shorter and shorter life. However, they struggled to live on though their intelligence was getting lower and lower. They finally survived, but with an average height of less than 100 centimeters.