Cities have expanded and multiplied rapidly in Developing countries worldwide due to urbanization. Urbanization can be a boon as well as a bane to the Environment. The purpose of this paper is to provide a broad overview of the recent trends of urban growth in developing countries, problems, and regulation regarding Urbanization.

Urbanization refers to the general increase in population and the amount of industrialization of a settlement. It symbolizes the movement of people from rural to urban areas. Urbanization happens because of the increase in the extent and density of urban areas.

Urbanization is caused by various reasons such as Industrial Revolution, for job opportunities availability of transport, migration, Infrastructure Facility in an urban area, better standard of living, diversity in Social Community, Growth of private sector. There are a number of reasons urbanization can be good for the environment if managed properly.

First, environment-friendly infrastructure and public services such as piped water, sanitation, and waste management are much easier and more economical to construct, maintain, and operate in an urban area. Urbanization allows more people to have access to environment-friendly facilities and services at affordable prices.

Secondly, urbanization brings innovation, including green technology.

Soon possibly environment-friendly equipment, machines, vehicles, and utilities will determine the future of the green economy and finally, the higher standard of living provides people with better food, education, housing, and health care. Urban growth generates revenues that fund infrastructure projects, reducing congestion and improving public health.

Though urbanization can be good for the environment, when not managed properly it can impact the environment causing many problems. The most emerging issues are climate change, freshwater scarcity, deforestation, and freshwater pollution and population growth. These problems are very complex and their interactions are hard to define. The Global Risks 2015 Report looks at four areas that face particularly difficult challenges in the face of rapid and unplanned urbanization is infrastructure, health, climate change, and social instability.

How does urbanization affect the Environment?

Urbanization can create impact Atmosphere and climate, lithosphere and land resources, hydrosphere and water resource and on biosphere Impact on Atmosphere and climate: it creates heat island, Materials like concrete, asphalt, bricks etc absorb and reflect energy differently than vegetation and soil. Cities remain warm in the night when the countryside has already cooled. Secondly Changes in Air Quality, Human activities release a wide range of emissions into the environment including carbon dioxide, carbon monoxide, ozone, sulfur oxides, nitrogen oxides, lead, and many other pollutants. thirdly, changes in patterns of precipitation, Cities often receive more rain than the surrounding countryside since dust can provoke the condensation of water vapor into rain droplets.


Impact on the lithosphere and land resources: Flow of Water into Streams, Natural vegetation and undisturbed soil is replaced with concrete, asphalt, brick, and other impermeable surfaces. This means that, when it rains, water is less likely to be absorbed into the ground and, instead, flows directly into river channels. Secondly, the flow of Water through Streams Higher, faster peak flows change streams channels that have evolved over centuries under natural conditions. Flooding can be a major problem as cities grow and stream channels attempt to keep up with these changes. Finally Degraded Water Quality, The water quality has degraded with time due to urbanization that ultimately leads to increased sedimentation thereby also increasing the pollutant in the run-off.

Impact on Biosphere: firstly there is a modification of habitats, The fertilizers that spread across lawns are discharged and the waste dumped into streams lowers oxygen levels during its decay and causes the die-off of plants and animals. Secondly, we Destruct Habitats, there is also complete eradication of habitats as an outcome of urbanization and native species are pushed out of cities. Thirdly, the creation of New Habitats, New habitats are also created for some native and non-native species. Cities also create habitats for some species considered pests, such as pigeons, sparrows, rats, mice, flies, and mosquitoes. Urbanization has, for example, eliminated many bat colonies in caves, but has provided sites such as bridges for these species to nest.

Impact of urbanization on the Environmental quality in Metropolitan Cities: Slum Situation in Cities, Total slum population in India according to size/class of towns during 1991 shows that 41% of the total slum population was residing in million-plus cities, where 27% of the total population of India resides. An estimated 72 percent of the urban population of Africa now live in slums. A large number of urban residents in developing countries suffer to a greater or lesser extent from severe environmental health challenges associated with insufficient access to clean drinking water, inadequate sewerage facilities, and insufficient solid waste disposal.

Waste Water Generation, Collection and Treatment in Cities, Water resources are diminishing not just because of large population numbers but also because of wasteful consumption and neglect of conservation. With rapid urbanization and industrialization, huge quantities of wastewater enter rivers. As we discussed various problems due to urbanization, we have many agreements, strategies at the international level as well as the national level for the welfare of the people.

The United Nations Conference on Human Settlements (Habitat I) in Vancouver in 1976, which adopted the so-called Vancouver Declaration, was the major starting point for urbanization (UN-Habitat, 2006), to promote socially and environmentally sustainable towns and cities with the goal of providing adequate shelter for all. Habitat-I regarded urbanization as a problem which ought to be contained by promoting rural development and lowering rural-urban disparities. An important outcome of Habitat I was the establishment of the United Nations Centre for Human Settlements (UNCHS) in 1978. The second United Nations Conference on Human Settlements (Habitat II), in Istanbul in 1996, adopted the Habitat Agenda. The two major goals of this agenda were ‘adequate shelter for all’ and ‘sustainable human settlements’ (UN-Habitat, 1996).

# Promotion of security of tenure throughout the developing world;
# Support for vulnerable groups, especially women and the poor;
# Provision of adequate and equitable access to basic urban services; and
# Promotion of decentralization and good urban governance.

We also have the new millennium, the UN hosted the Millennium Summit, gathering more than 150 heads of state who adopted the so-called Millennium Declaration (UN General Assembly, 2000). One of the Millennium Development Goals (MDG), which has been laid out in this declaration, explicitly states ‘By 2020, to have achieved a significant improvement in the lives of at least 100 million slum’.

The United Nations Development Programme (UNDP) 1965: The United Nations Development Programme (UNDP) is the United Nations' global development network. Headquartered in New York City, UNDP advocates for change and connects countries to knowledge, experience, and resources to help people build a better life. It provides expert advice, training and grants support Other major developments include the foundation of a local authority network, named United Cities and Local Governments (UCLG), in 2004, and the establishment of a Commission on Social Determinants of Health (CSDH) by the World Health Organization (WHO) in 2005.

The CSDH is based on several knowledge networks, one of them being the Knowledge Network on Urban Settings (KNUS) which has recently published its final report on the often life-threatening urban conditions, their social determinants, health consequences and possible interventions (KNUS, 2008). For 2010, KNUS plans a ‘Global Forum on Healthy Urbanization’ (KNUS, 2006).
Some notable program regarding urbanization in developing countries,
# The UNDG Guide for Integrating Urbanization into CCA and UNDAF (2015)
# Urban Governance for Sustainable Urban Development Guidance Note(2014)
# The UNDP Strategy Paper on Urbanization in Asia and the Pacific (2013)
# UNDP Guidance Note for Urban Programming Asia and the Pacific (2015)

We also have strategy programs and policies under the national level for urban development, the two urban-related ministries at the national (GoI) level- the Ministry of Urban Development (MoUD) and Ministry of Housing and Urban Poverty Alleviation (MoHUPA). The Government of India's overarching urban development objectives is to create economically productive, efficient, inclusive and responsive ULBs, by focusing on strategic outcomes:
(i) universal access to a minimum level of services;
(ii) establishment of city-wide frameworks for planning and governance;
(iii) modern and transparent budgeting, accounting and FM;
(iv) financial sustainability for ULBs and service delivery institutions;
(v) utilization of e-governance;
(vi) transparency and accountability in urban service delivery and management;
(vii) Slum-free cities.

In pursuance of these goals, the Government of India (GoI) launched a flagship urban development program called the Jawaharlal Nehru National Urban Renewal Mission (JnNURM), in December 2005. The Mission targets 65 ULBs (7 with populations greater than 4 million, 28 greater than 1 million and 30 other ULBs of religious, historic or tourist importance). JnNURM is reform and incentive-based - in return for a commitment to adopt the obligatory reforms over a period of seven years, ULBs may access funds for investment and capacity building.

The investment component of the Mission consists of two sub-missions:

(i) Urban Infrastructure and Governance (UIG), implemented by the Ministry of Urban Development (MoUD), with investments including
(a) water, sanitation, sewerage, and drainage;
(b) solid waste management (SWM);
(c) urban transport;
(d) street lighting; and
(e) environmental protection; and

(ii) Basic Services to the Urban Poor (BSUP), implemented by the Ministry of Housing and Urban Poverty Alleviation (MoHUPA), with investments supporting integrated development of slums. More recently GoI launched the Slum-free City program of Rajiv Awas Yojana (RAY) a scheme working towards the goal of a slum-free India. we also have smart cities project, the Government of India has launched the Smart Cities Mission on 25 June 2015. The objective is to promote sustainable and inclusive cities that provide core infrastructure and give a decent quality of life to its citizens, a clean and sustainable environment and application of Smart Solutions.

In addition, many of the state governments have their own urban development schemes and programs at the state and level, focusing on many of the aforesaid issues.

Conclusion
Thus, the causes of damage to the environment due to urbanization lies in the legislation and the regulating agencies of the country. To overcome the problem we need to ensure green urbanization, developing countries need to continue the downward shift by adopting the following recommendations. The first priority is to improve energy efficiency and conservation through appropriate pricing, regulations, and public sector support. It is vital to get prices right so that they incorporate the full social costs and benefits and ensure the efficient allocation of resources. This can be done by imposing congestion and emission charges. Countries need to introduce regulations and standards in a timely manner. These can correct for market or coordination failures on air, water, vehicles, and appliances, as in India. The government can build green industrial zones to attract manufacturing, as in Indonesia.

Cities need to build rapid public transport systems to improve connectivity and reduce pollution. Speedy connections to and from satellite cities can ease congestion in central megacity hubs. The second priority is to promote renewable resources and new energy technologies.

Waste-to-energy plants reduce pollution and generate energy, as in the Philippines and Thailand. Green technology can be acquired either by importation or innovation through research and development, as in the PRC. The third priority is to help the poor by reducing disaster risks and improving slum conditions. Disaster risk reduction can be done by building dwellings in safe areas, improving housing affordability for the poor, and investing in drainage infrastructure and climate forecast technology.

Policies to improve slum conditions include providing basic services, granting land titles to slum dwellers, and issuing housing vouchers linked in value to the length of a resident’s tenure in the city. The fourth priority is to strengthen public finance, transparency, and accountability. Public finance can be improved by broadening the tax and revenue base and by increasing the access of urban governments to broader and deeper capital markets in order to lower infrastructure and public service costs.

Failure of governance in today’s cities has resulted in the growth of informal settlements and slums that constitute unhealthy living and working environments. Serious attention should be given to the need for improving urban strategies, which promote efficiency in resource use.