Which country contribute the most air Pollution/global warming?

Yes, that is probably true, although it depends what way you look at it. Some countries may seem to contribute much less to global warming, but if you take into account the population then the figures can come out different. Australia for example is one of the greatest contributors to global warming per head of population. China as a country is about to overtake the USA as the greatest contributor, but per head of population they will still contribute far less. Then you can look at groups of people within a country. Rich people in India for example contribute far more than poor people in the USA.