The document discusses migration theories and policies related to rural to urban migration. It describes how urban areas are classified based on population size and occupations. Urban planning involves zoning areas for different uses like industrial, residential, and commercial. Massive rural to urban migration in developing countries is driven by push factors like poverty and lack of opportunities in rural areas, and pull factors of perceived better opportunities in cities. However, large scale migration also leads to issues like overcrowding, increased pollution, and unemployment.