133 We are also and equally concerned for the lot of those who are forced to leave their native lands because they cannot earn a living there or because of intolerable conditions and religious persecution. They must undergo many inconveniences and hardships when they go from their native land into foreign countries. Oftentimes, in crowded cities and amid the noise of factories, they must lead a life very different from the one they once knew.
Source: Ad Petri Cathedram (Vatican.va)