The immigrants are persons that have to move another country because their country dont let to live with the minimum standard of life. It is one of the most important reason. However may be exist other reasons about it.
The process of immigration is around the world. Some countries has been working so hard to create the conditions to receive them according the international roles. It phenomenon has caused bad feelings in some countries because they don't want to share their land with anybody. It has produced very hard emotions that reach the racism in the expat but by the other hand there are many situations caused by the bad behavior of immigrants. For that reason they have faced hate crimes.
