Urbanization first began in ancient Mesopotamia in Uruk period (4300-3100 BCE); it continues from 18 centuries and until now, it has not yet reach it peak. Urban areas are areas with high population of humans, infrastructure, built environment and resources availability; it includes cities and town that have 1000 people per square mile. These areas are established through urbanization and are categorized by urban morphology such as cities,towns, suburbs or conurbations. Urban areas are areas that offer employment, food, shelter, good transport services, commercial services, medical services and education to their inhabitants. Many people on a daily basis are still moving from rural areas to urban areas for the search of non-agricultural jobs and better lifestyle.

Definition of urbanization

According to Kingsley Davis, urbanization is defined as the shift of population from rural to urban areas or a change in the ratio of the total population living in urban areas. Urbanizationdescribes both the increasing footprint of urban areas and the increasing percentage of the urban population; this is closely linked with modernization, industrialization, and the sociological process of rationalization.

Urbanization can describe a specific condition at a set time, i.e. the proportion of total population or area in cities or towns, or the term can describe the increase of this proportion over time. Urbanization is not merely a modern phenomenon, but a rapid and historic transformation of human social roots on a global scale, whereby predominantly rural culture is being rapidly replaced by predominantly urban culture.

Source: Carter 1995

The urbanization process is due to two main factors or processes such as

• Migration into the cities (mainly rural urban migration)
• Natural or internal population increase in the cities (this is due to excess number of births over death).

Urbanization is usually explained with a curve with an S shape as shown below

Picture showing urbanization curve

The urbanization process is further divided into four phases as indicated in the picture above.

1. Phase 1– This is the initial stage which is an agricultural /primary production phase
2. Phase 2– Acceleration stage or industrialisation phase. For instance, most third world countries including Nigeria are in this phase and they are characterised by exponential growth of their urban population s growth.
3. Phase 3– The mature stage or post-industrial phase; in this stage, urbanization starts to flatten up and stabilises, however, most North Western European countries, USA, Canada are in this phase.
4. Phase 4– this is the final phase and it is uncertain what will happen in this phase, but two scenarios are likely to happen such as:-

• Urbanization will continue to increase until the country is 100% urbanised. Japan is one example of such urbanised countries.
• Large cities will lose their population and may witness decline in urbanization leading to counter-urbanization or deurbanization. Large Western cities like London, Paris and Amsterdam etc. are witnessing gross decline in their population.

Factors that determine urban development

So many factors determine city growth; these factors may include migration, economic activity, modernised life style, political services among other factors. Many countries of the world have their different criteria for defining an urban city. The word urbanization could be defined based on city size and population size. For instance, in Nigeria, the minimum population for asettlement to qualify as urban is 20,000 and above, hence some other countries could use a population size of 5,000 of people to define an area as urbanised. However, population size alone is not enough to describe an area as urban, but other criteria like-

1. Population density– density can be measured in different ways such as per square kilometre, per square hectare, number of bed spaces per hectare, number of dwelling units per hectare and so on. based on whatever method urbanization is measured; population density is much higher in the urban areas compared to the rural areas.
2. Density of physical development– urban areas are characterised by compact and high density of physical development such as road, railways and airparts.
3. Possession of formal plan– some people have to contrast urban and rural areas in terms of a formal physical plan. For Instance, the Jos-Bukuru Master plan of 1975 defines the way the town was to grow and developed over 25years period. Some rural areas also have formal physical plan and this is therefore not a good measure of urbanization, however, in some developed countries, all settlements irrespective of their sizes have land use plans.
4. Proportion of the inhabitants engaging in non-agricultural occupation– it is argued that most inhabitants in urban areas are involved in secondary and tertiary activities unlike in the rural areas where most people are engaged in agriculture or other primary occupations. In addition, this may also be an important criterion as most inhabitants in places like south- west (in Nigeria) are engaged in farming. Similarly, a large proportion of people in many Chinese cities are also farmers.
5. Functional characters– Urban areas are centres of trade, commerce, learning, tourism technology and manufacturing; it allows exchange of ideas and even distributions of natural resources.
6. Number and range of services– it follows from above that urban areas offer a range of many and complex services when compared with rural areas. Different forms of urbanization can be classified depending on the style of architecture and planning methods as well as historic growth of areas.
7. Administrative, legal or political criteria– All the states capitals and local government headquarters in Nigeria for instance are officially designed as urban areas irrespective of their physical and population sizes.
8. Life style– urban lifestyle is obviously different from that of rural areas; this is commonly seen in their clothing pattern, type of food, socialization and on the general life style of the people.

Causes of urbanization

1. Economic development– the industrial Revolution of the 17^th and 18^th centuries greatly accelerated the space of urbanization as people moved into cities for employment and other economic opportunities; however, urbanization and economic development always go hand in hand.
2. Industrial Revolution– once an area is industrialized; it gives way to high number of migrants. Industrialization has brought about urbanization by creatingeconomic growthand job opportunities which draw people to cities. The urbanization process typically begins when a factory or industries are established in an area; this establishment brings about a high demand of skill and labour to specialise I different department of the say factory. Other businesses such as building manufacturers, retailers and service providers then follow the factories in order to meet the product demands of the workers, thus, this creates even more jobs and demands for housing, thus creating an urban area.
3. Job Opportunities– what differentiates cities from rural areas is the availability jobs and other commercial activities. Job opportunity is an important factor that draws people from the rural areas to seek better livelihood in the city. However, there are certain number of people who frequently migrate into urban areas to access well-paying jobs as urban areas have countless employment opportunities in all developmental sectors such as public health, education, transport, sports and recreation, industries, and business enterprises. Services and industries generate and increase higher value-added jobs, and this leads to more employment opportunities in urban areas.
4. Availability of easy transportation– the gradual increase in the proportion of people living in urban areas or cities could also be linked to the development of public transport systems which facilitated commutes of longer distances to the city centre for the working class. The creation of cities brings about reduced transport costs such that prevents one from having to travel a long distance from the rural area to places like markets or factories, but rather provides a choice for one to decide whether to live near the office or make use of public transport to work.
5. Agglomeration economies– urban areas provide infrastructure, services, skill, labour and capital that attract new investments to be located in such areas. The initial leads to cumulative growth of the cities. Evidence abounds that large cities grow faster than small cities and towns. Example is the case of Lagos in the 1960s and 1970s.
6. Political, cultural and social influences– most third world urbanisation is propelled not by economic development or industrialisation, but the lure of the city, people perceive the city as providing a better standard of life to the rural areas and they decided to migrate there. Additionally, the colonial experience in Nigeria for instance, was an important phase in urban development and increased urbanization rate. This era influenced the growth and pattern of urbanisation in many ways, including the creation of new towns, principally along the transportation routes and at the ports and mining camps. There were also the establishment of the physical structures, modernisation of existing towns, introduction of modern utilities and changes in the economic base, which led to the emergence of modern commercialindustrial centres outside the traditional town centres. The created state level of government has had perhaps the most significant impact by introducing new poles of political and economic growth. Consequent on all these pull factors in towns and cities; the city centre.

Urbanization problems

Industrial cities were difficult places to live in due to Public health issues resulting from contaminated water and air and the spread of communicable diseases due to overcrowding. This further led to insufficient space for expansion houses, public utilities, and costly building materials, which can only be afforded by few individuals. Some of the major problems of urbanisation are described below.

1. Unemployment and under employment– urban areas battle with a high rate of unemployment on a yearly basis; for instance, imagine the many institutions in the country and also the number of graduates that are graduating on a yearly basis with the current job situation which the whole country is facing. What do you think will happen if the fresh graduates are coming to meet with old timers who have been waiting at home before them? The truth is, even if there are jobs for such graduates, how many of them will be employed coupled with the fact that there are other ones searching for the same opportunity? In this case, there will be much graduates crowding the city with less or no job for them, hence, poverty, unemployment, little income and high cost of living will be become the order of the day.
2. Shortage of residential housing– Urbanization allows the movement of people from the rural areas to the cities and towns which in turn results in population increase. Increase in the number of people living in urban areas often results in continuous scarcity of houses and a large sparse of land is also demanded for further spread of settlement.
3. Poverty- poverty causes malnutrition and illness; it is a major cause of mental stress and loss of self-esteem especially among young people, which may lead to depression, and may further have some negative impacts on the health of adults.
4. Competition on limited resources-Urbanization problem makes people to depend on others for necessities; urban-dwellers must rely on the rural dwellers for agricultural production, for instance, because city residents do not have enough land to grow their own food. Urban-dwellers suffer the psychological degradation that comes from depending on other people to accomplish the activities of daily life, from transportation to education and entertainment. In addition, strains on important natural resources, such as water supply, food, fuel and land uses lead to higher prices and general environmental sustainability problems.
5. Sanitation urbanization result in rapid population in the city, most of these cities are not properly equipped to handle large populations and their sanitation needs. In this case, it is common to find out that there are inadequate sewage facilities, poor sanitation and contaminated cabbage being drained into the neighbouring streams, rivers, lakes, or seas which eventually leads to the spread of communicable diseases such as typhoid, dysentery, plague, and diarrhoea andeven death.
6. Epidemics cities that experience poor sanitation are mostly those that are overcrowded, this is particularly caused by poor and insufficient water supply, air pollution and other environmental problems which expose the urban areas to various diseases like allergies, asthma, infertility, food poisoning, cancer and even premature deaths .
7. Pollution problem- pollution is mostly caused by effluents, smoke, smog, fume and spillage, all these contributes to spread of communicable diseases and also result in contaminated water and air in an overcrowded area
8. Transportation- over population in an urban area often results in poor transport system, road congestion, stress and limited number of public transport.
9. Social vices insufficient resources and social amenity may lead to many social vices such as poverty, lack of opportunities, psychological problems, theft, rape, alcoholism, drugs, crime, violence and other deviant behaviours. These acts of urban crime normally upset the peace and tranquillity of cities/town.

Congestion, scarcity of houses and competition are some of the problems of urbanization

Solutions to urbanization problems

1. The problem of urbanization can be solved if government will decide to create a law guiding birth increase; these can be achieved by setting up campaigns and counselling programs to teach most especially the women on effective family planning practices to help reduce high rates of population growth in urban areas. These programs should be made accessible across the entire city and towns.
2. The problem of congestion is mostly created as a result of people trying to use private vehicles instead of public vehicles. This choice is simply made for the reason of convenience and to reduce cost, along the line, the decision increases more vehicles, hence, causing air pollution and congestion, thus leading to more energy usage. The major solution to traffic congestion is – Governments should increase public transportation and encourage people to make use of the public transport, while reducing the number of private transport in the urban areas to prevent traffic congestion. By doing this, air and noise pollutions are reduced and more energy is conserved for the future generations.
3. To prevent shortage of residential housing, government should make life better for the rural dwellers; an effectual way to do this is to make the economy of village and small-scale industries fully viable. This will keep the rural dwellers from migrating to the city that is already crowded, and then attract people leaving in the city to move to rural areas for a simplicity and comfort.
4. Social mechanisms should be developed in cities and towns to reduce inequality and make sure the basics amenities and infrastructures like health, new roads, clean water, sanitation and education reach those who have been underprivileged of the same opportunity.
5. There should also be a development of sustainable urban sanitation facilities for the urban dwellers by converting faecal waste, sewage with other organic waste to methane to reduce the impact of pollution and poor sanitation on urban population.
6. Government should create more jobs by establishing industries, supporting private investors, and should encourage entrepreneurshipby providing more funds in the urban areas. This will go a long way to encourage hard while reducing the number of unemployed graduates in the city.
7. Governments should develop some strict laws guiding refuse dumping in an open environment in other to prevent water pollution, air pollution and land pollution. These will help control contamination and prevent the spread of communicable diseases in the urban areas.