The provided bar graph depicts the changes in air quality levels caused by electricity generation, transport, and industry across China, America, Japan, and Australia in the year 2021. Overall, industrial air pollution was the major reason for air pollution in most of the countries, except America. In contrast, Australia was the only country with the least air pollution caused by all three sources.
In China, industrial pollution was at around 80 PPM, followed by transport and electricity generation with 70 PPM and 59 PPM respectively, marking it as the most polluted air quality among all other countries. Conversely, in Australia, all three causes were relatively similar, below 20 PPM, which is significantly the least polluted air.
Transport was the major reason for pollution in America with 58 PPM, while industry was least responsible for it, followed by electricity generation at above 30 PPM. Japan has significantly low pollution in the air, in which industry was at 42 PPM, whereas electricity generation was at 15 PPM and transport was roughly at 30 PPM.