Is it just me, or is there some bias in the before & after photos?

Mexico city "before" is just one dwelling versus a full street in the "after".

Nairobi "before" is taken when most of the city was dark due to clouds, whereas the "after" is a bright, sunny day.

Similarly, Shanghai "before" looks like it was taken with an unfavourable filter on a hazy day.

I'm not doubting that the world is improving, especially in those places. I just find it unusual that they used such obviously biased photos.