Overcrowding and slums developed in many impoverished countries in the 20th century, mostly due to large migrations to cities from people looking for work.
Changes in pressure cause wind to blow.
"The Midwest receives the nickname of "breadbasket" because of the abundant cereal crops it produces for the United States and the world; these crops include wheat, corn and oats. The history of staple cereal crop production in the Midwest dates back to the 1700s. The fertile soils of the Midwestern states and availability of cheap, abundant land proved suitable for launching a large-scale farming effort, ultimately leading to high volume production of predictable and reliable crops" credit to google put it in ur own word
