Push and Pull Factors
In Iran those who belong to ethnic groups such as Azeris, Kurds, or Sunnis have gone through ethnic persecution. If they aren't a Muslim group they are persecuted by illegal search and confiscation, unlawful arrest, torture, or even death. Pushing them away.
To get away from that many of them go to Australia. To get protected and to apply for a visa.
North Korea has a high religious persecution rate for hating Christians. Christians are forced to meet only in secret, they cannot even share with thier Families. Or they could get tortured, arrested, or executed. That pushes them away. Many of them flee to South Korea or even China.
Sudan lacks supplies for holding water, declining wildlife populations due to warand excessive hunting, periodic droughts, and soil erosion. Thier enviromental factors involve lack of food because of hunting and soil, and poverty. People are often pushed away fromSudan because of these conditions. Sudan also has been affected by falling oil companies, causing rises in inflation and devaluating the currency.
Mexico. People who live in Mexico don't have a lot of jobs to choose from, and it's very hard to find work that has good pay to support you family. Often times people from Mexico will come to the U.S.A. Or another place, to find a decent job and send money home to their families
Cuba has dictatorship. Thier freedom of speech is censored on TV, books, and newspapers. They have very little freedom and tremendous political persecution. Anyone contesting the governments rule is arrested. They often flee to Florida because it's close. Cuban citizens cannot leave or return without official permission, which is rarely granted
The United States once had forced migration known as the trail of tears. Many native Americans were forced out of their homes. They had to walk to the reservations. It was cold and many died along the way.