all around the wold large cities have the same problems.that problem is alr pollullon.mexico city has very bad air.the air there is dirty and very unhealthy.cars are one reason for the dirty air.many mexicans now own their own cars and drive in the city. the factories in the areas also cause air pollution.these factories put a lot of smoke into the air.lt is not easy to clean up the air in a large city.the government has to make
new laws and everyone has to help