
Given the following passage

"In the Middle East, and particularly in Iran, Genghis Khan is almost universally condemned as a destructive and genocidal warlord who caused enormous damage and destruction to the population of these areas. Steven R. Ward wrote that "Overall, the Mongol violence and depredations killed up to three-fourths of the population of the Iranian Plateau, possibly 10 to 15 million people. Some historians have estimated that Iran's population did not again reach its pre-Mongol levels until the mid-20th century."",

answer the following question. Note that the answer is present within the text.

Question: What was greatly reduced as a direct cause of the wrath of Khan? 

the population
