Can you attach a picture maybe?
The common geographic factor for Egypt and the fertile crescent were the big rivers, they made big alluvial deposits on their shores each year and allowed the people to have sufficient amount of food production. That opened the gates for civilizations to flourish in this places.
The vast pollution which occurs globally can have a significant impact on air quality on a local scale. The reason for this is quite simple: polluted air can easily get trapped beneath a cloud cover, or be literally "blown" away to other locations, and when much polluted air gets accumulated, it can have devastating heath effects on a local population, not just to humans, but to animals and plants as well. Overall, the vast global pollution can effect the smallest of regions on an unprecedented scale.
The lowland river system.
It is
75÷100= .75
I think
and your welcom