why pollution is a global problem not limited by political boundaries?

Answer 1

because there are no customs and immigration officers verifying the border crossing rights of the chemical and physical pollutants.

In other words, water and air (and any pollutants being carried) migrate where they migrate, without regard to the arbitrary and non-physical (imaginary) political boundaries.

As an example, in Sudbury Canada, pollution from the metal smelter caused heavy metal and acidic pollution in the immediate area until they had the brilliant idea to raise the stack higher. The end result was the arrival of heavy metals and acid rain in Scandinavia that originated from Sudbury. They just transferred where the problem occurred. The pollution didn't float to the border of Ontario (or even Canada further east) and then stop, saying oooops gotta stop here.

Answer 2

Air pollution is found to be more over the cities.Not all the air pollution produced in cities is confined locally.Pollutants can be carried downward,sometimes for long distances,even crossing national frontiers.There,they are liable to cause severe damage to lakes and rivers,forests and agriculture.That damage,in its turn,may have an impact on the food and water on which the cities themselves depend.So, it is considered as a global problem.

Answer 3

Pollution is a global problem because politicians has nothing to do with it and it's a problem for all of us.