There are many factors such as 5% of Mexico's population is undernourished then 88% of Mexico has access to clean drinking water, Average hourly wage is $3.49 therefore Unemployment is high in Mexico and rising 18% of Mexico lives on less than 60p per day, 2 out of 10 people have a car and then Little government spending on healthcare and education. As we look to USA that can attracts the Mexicans which are Almost 0% undernourishment in USA,then  Average wage in California is $6.75
Access to quality healthcare and education ,8 of of 10 Americans own a car and Less than 1% of the USA lives on less than 60p per day and many others.
As we look to USA, the government has several impacts such as As a result of the vast numbers of Mexicans moving to California a number of things have happened:
Local businesses have benefitted as they now have a source of cheap labour
Mexicans are prepared to do many of the jobs that Americans do not want such as fruit picking or factory work
Large numbers of Mexicans have brough their culture and food with them making Mexican food very popular in California.
However, many Americans feel that Mexicans are taking their jobs. The USA government is trying to manage this migration by several actions;
The USA has tried to limit the numbers coming accross with fences and lots of border patrols; Some migrants come accross legally but as many as 3 million per year are coming accross illegally.
Many Mexicans are becoming desperate and resort to drastic measures.