Social Mobility is –
From rural to urban areas for work
Industrialization
Interaction between cultures
Movement in socio–economic stratas
Social mobility

Social mobility is the degree to which an individual's is family or group's social status can change throughout the course of their life through a system of social hierarchy or stratification.
The individual or family can move up or down the social classes based on achievements or factors beyond their control.
If such mobility involves a change in position, especially in occupation, but no change in social class, it is called "horizontal mobility". Example → a person who moves from a managerial position in one company to a similar position in another.
If the move involves a change in social class it is called "vertical mobility". Example → An industrial worker who becomes a wealthy businessman moves upward in the class system.