Final answer:
The Athenian immigration policy during Pericles' era caused social and economic divisions by requiring both parents to be Athenians for citizenship and led to overcrowding during the Peloponnesian War, resulting in a devastating plague.
Step-by-step explanation:
The dangers of the Athenian immigration policy, as observed in antiquity, largely stem from economic and social tensions between native citizens and immigrants. One notable aspect of this policy during Pericles' leadership was the requirement that both parents must be Athenians for a child to attain citizenship, which potentially alienated non-Athenian residents and had the unintended consequence of excluding some from participating in the political life of the city-state. This form of immigration policy elevated the status of Athenian women but also led to a sense of Athenian superiority and exclusivity.
These policies not only created social divisions but also had significant implications during times of crisis, such as during the Peloponnesian War when a plague broke out due to overcrowding within Athenian walls after residents were urged to move inside the city for safety.