CNG.

This city, like all cities in China, have a large amount of taxis and buses. There are still a lot of bicycles, e-bikes, motorcycles and mopeds. Some cities don't allow bicycles, e-bikes, motorcycles or mopeds. They feel that the public transportation is good enough without having the problems, such as cluttering the streets and sidewalks and weaving dangerously through traffic. Some cities have subway systems. It seems here, that there are just as many taxis as there are any other vehicles. Most of the taxis and all the public buses run on compressed natural gas (CNG). China's population is still growing and more of the people are moving to the cities. Because of the 'one child policy' the average age of China is getting younger. This younger, wealthier and freer younger generation has caused China to become the largest market in the world for automobile sales. With all the cities growing both with population and cars, the problem of smog and air pollution are also growing. To help fight this China has put into place policies that have led to the widespread use of CNG vehicles in mass and public transportation. China is cleaning up its act; what about the USA?