The facts of the matter are unimportant to the producers, the commissioners or the institution. It's *all* story -- narrative.
No, 90% of the population do not "breathe in toxic air".
Even if it were true, what is the context? The entire population lives far longer than ever before.
What counts is what gets measured.
So, yes, a team of ecological activists scientists from Western green NGOs can go to Mongolia, and measure the declining air quality. But...
That perspective reveals that, whereas infant mortality in the 1950s might be as high as 50%, today it will be 0.5%, despite "toxic air".
They don't care about the inconvenient facts. They don't care for context. They're not interested in historical perspective.
They are a propaganda outfit. End of story.