Question

why do we consider increasing concentration of carbon dioxide as pollutant

Answer 1

If an orange is called orange, then whyisn't a lime called green or a lemon called yellow? The colour is namedafter the fruit - not the other way around. Before oranges were imported to English-speaking countries, there was no specific word in English for that colour range.

Answer 2

hey,

Carbon dioxide is considered as pollutant because it is responsible for global warming. Moreover,  it is detrimental to human health also. Carbon dioxide is an asphyxiant  which cuts off the oxygen supply for breathing in confined spaces.