The population of Cahokia began to decline during the 13th century, and the site was eventually abandoned by around 1350. Scholars have proposed environmental factors, such as environmental degradation through overhunting, deforestation and pollution, and climatic changes, such as increased flooding and droughts, as explanations for abandonment of the site. Political and economic problems may also have been responsible for the site's decline. It is likely that social and environmental factors combined to produce the conditions that led people to decide to leave Cahokia.