The documentary the components of smog, its sources and what we should do. Let's talk about the components first. It is made of carbon produced by coal and oil combustion. The linear structure of these carbon can be stretched into two football fields! Hidden in these carbon structures are many carcinogens.
To reduce emissions, it should be reduced from the source. So what are the sources of it? All kinds factories using coal as fuel and car exhaustions. Although China has the environment department and laws to reduce emissions, but it is frustrating that the environment department can not apply real enforcement. For example, in the film a private gas station's boss said to the journalist "The environment department has the obligation but no right to check on me." Also, because there is no law of regulatory enforcement which leads the manufacturers to be not in accordance with the emission standards, or manufacturing fake trucks that meet environmental standards.Their reasoning was - "since everyone else is not doing it, why should I? Or else I am the idiot that don't make money".
Similar environmental pollution tragedies occured in London and Los Angeles, but they later regained their blue skies through effective legal control.
However, in the last part of the film it has a positive spin. If everyone can reduce emission or report any incidents that you think it not up to standard, then reduction or even elimination of smog is not impossible. It also makes me think that I can not take Toronto's quality air for granted. It requires everyone's awareness and care.