Back in the late 1980s I spent 4 months in and around Cholula, Mexico, and I can tell you that I only saw this view like twice the whole time I was there. The rest of the time the volcano (“Popo”) was obscured by smog, clouds, etc. Mexico City is on the other side of the volcano and Puebla (a big city too) is behind all this so between the two there was always smog up there even though where I was was pretty rural and Cholula was not then a big city. Air pollution sucks.
MATTHEW'S ISLAND
MATTHEW'S ISLAND 
I think the air pollution has gotten better over the years, Matthew. I was at this very spot in November last year, and it was quite clear. Of course there are still days with bad pollution–here in Guadalajara, too–but it is improving.
I’m glad to hear that the air quality is improving. But, man, when I was there the air in Mexico City in the late 1980s was so bad I actually got a lung infection (pneumonia) from it.