They built a better currency trade so people could buy what they want without plying redicious amounts of money. the bisnusses were not making enough money, the great depression started arround 1929 so the great depression would be a cause of there spending habbits.
Afghanistan became an independent state when Amanullah established an alliance and signed a treaty of friendship with the Soviet Union. Hope this helps if you have any questions please feel free to message me;)
1 The United States was concerned about renewed European colonization efforts in the wake of Latin American independence movements.
Violations of the neutrality of American ships