Compact cities are generally attributed with important benefits (socials and economics) connecting with high density. However, the high density can mean significant impacts (environmental, healthing and climatology). For example, if the buildings are too close, natural light cannot penetrate in the flats and it is needed more artificial lighting. Also, the rate of mortality could be increased because high density can make worse the quality of air. So Compact City can become unsustainable.

In my opinion, it is most important paying atention in the design of de city than in the concept of compact city. Planners should design the cities with sustainable criteria. This criteria should allow the negative impacts will be limited. 

With regards to the necessary attributes of a sustainable city, have a look at Constantinos Doxiadis's book "Ekistics: An Introduction to the Science of Human Settlements"  pages 288 to 316 published in 1968 in which he sets out statistical "laws" of development. However, be aware that his vision of Ecumenopolis, a global scale city, was well off target as he was unaware of physical limitations of the carrying capacity of Earth. In 1978 I incorporated a number of Doxiadis's relevant "laws" in a Summary of Steady State Settlment Patterns matrix which does include the physical principles of Steady State. This summary, "Ekistics and Energetics: A Sustainable Future Planning Approach", was published in Urban Ecology in 1979 and can be downloaded in ResearchGate. Empirical energy analysis studies of high density cities sorely need to be made in order to avoid making dramatics mistakes in urban planning within the context of a low energy future. Also have a look at Christopher Alexander's et al. book "A Pattern Language: Towns, Buildings, Construction" published in 1977 for a humanistic approach towards urban planning.

Compact cities may deprive people from the contact with more natural settings, but not necessarily. There are still several degrees of freedom, a important one being tax incentives for people to live close to the place they attend to work or study. However, a known research by Kenworthy and J.R. ; Laube, (F.B.Automobile dependence in cities: An international comparison of urban transport and land use patterns with implications for sustainabilit, Environmental Impact Assessment Review, 1996, Vol.16, pp.279-308 ) shows population density and transportation energy consumption to correlate according to a hyperbole. However, such correlation there is a statement about material sustainability alone. The notion of sustainable was originated in Forestry and is well applicable to a rather closed system like a forest. However, when one speaks of a sustainable city, he/she cannot mean everything (resources, environment, society, politics) with a similarly quantitative approach. It is important that scientists give up making statements on what is sustainable. Centuries. millennia must have gone before such a statement can be done.

One of the main attributes of the Compact City is the efficient use of the land, because land is one of earth's finite resources, needed not only for urban use, but for agriculture and environmental preservation (water, biodiversity, etc.). Compact Cities preserve unbuilt land, opposite of  disperse cities or urban sprawl, growing almost infinitely,  with low density housing, which means high costs for roads & services and the unfeasibility of a transportation system other than the private automobile, leading to a bigger carbon footprint.

Compact city is one main consideration in urban sustainability. It targets better land use patterns. It requires new ways in city planning, Urban Design, transportation and Housing. It dose not target reduce the land use but create efficient and interrelated relationships between the different functional components of the city. According to sustainability principles, the compact city has to create livable city with a high quality for the nature and all types of users. Therefore, compact city is not only concentration but a real challenge to bring all urban functions to a new relationship where resources, environment and society can benefit from it.  

Md. Fuzail,

Compact city is the opposite of diffuse city. It is not necessarily high density. What is important is the diversity of activities in every part of the city. Economic, social, cultural, housing, government and so on. It is sustainable because it reduces mobility, reduces energy consumption and reduces carbon footprint.

compact city by itself doesn't equal sustainable city. Sustainable cities do have many attributes to be achieved. These attributes should be first analyzed, tested, do alternatives then design a city that have a balance between these  attributes.  Each city has its' own characteristics: environmental, social, and economical components. So it's not easy to say a compact city is sustainable.

To explain my answer widely please check the following interesting link

http://www.intechopen.com/books/climate-change-research-and-technology-for-adaptation-and-mitigation/what-is-green-urbanism-holistic-principles-to-transform-cities-for-sustainability

The intrinsic principle behind the creation of compact cities is both to respond to impending scarcity of land resources as well as reap the benefits of urban agglomeration via sustainable use of resources and hence reduced energy and carbon budget, optimized accessibility to community resources, efficient public transport system and enhanced social capital. An efficient underlying design can only facilitate such a model. Over the period of several decades, we have evolved forward from the broadacre cities of early 1900s in the US to the high density compact cities supporting extensive knowledge economies; Singapore, Tokyo and Hong Kong as examples in Asia. This has been in a way goaded by factors including the future likelihood of resource scarcity, environmental considerations, economics as well as population health. In a nutshell, the underlying objective is and should be optimized resource utilization and hence future sustainability and those compact cities that fare poorly in their sustainability rating must move towards it.

A compact city is simply easier to manage but when examined on which ever principle of sustainability you choose it will be become obvious that it is not necessarily sustainable. A compact city is simply maximising its potentials while a sustainable city optimizes. 

A compact city might not necessarily be a sustainable one. The issue of sustainability concerns, generally, issues of economy, environment, and social concerns. A compact city is directly related to density, increased mixed land use and integrated planning approaches. The implementation of these may not necessarily conform to sustainability. For example, increasing density might be looked as limiting the quality of life, as in reduced open spaces. The implementation of a compact city, while considering issues of sustainability, and depending on location, may have to consider sacrifices of one to achieve the other- tradeoffs as many commentators refer to them.

The adjective "compact" concerning the definition of the city is in itself a definition as another.

a slogan

a slogan easy and useful to fill many infographics

Near the adjective "compact city" require additional definitions

The city is the result of a holistic process ongoing

In this historical period the researchers do two things:

1 search-and systematize big data (perfect recipe?)

2-seek the synthesis between the economy, environment, society (eco-sustainability?)

few continue to progettarela city

which is then compact or not, this is just one of its values

Thank You all for such a valuable inputs... i have been a bit busy these days, will try to discuss a bit more shortly!

thanks again!

 Compactness implies energy savings in infraestructure and thermal conditioning (heating) apart from social consequences.

If you want, you can take a look to this article in Elsevier website:

Building porosity for better urban ventilation in high-density cities- A computational parametric study by Chao Yuan*, Edward Ng

The compact city takes place when a high proportion of land surface is covered by buildings, structures and other man made surfaces . Many cities contains area with high development density in down town or old urban core. Some the other cities develop new compact area or redevelop exiting zones to a higher density that is why in developed countries more people choose to live in the urban fringe or rural areas.

I think Fuzail refers to density increase in contemporary cities as a way to sustainable development. Sun access is one of the problems that arises when skyscrapers populate large urban areas. It becomes difficult to achieve energy from renewable sources: solar energy for sanitary hot water or PV electricity. Apart from that, outdoor public space becomes uncomfortable because of pedestrian wind. I expect this could be useful for your research.

Thank you Patricia and all!

but the question is what could be the other alternatives rather that to go for compact development especially when there is high growth rate of population as well as urbanization especially in the developing countries like India.....

the land resources are limited and we have to accommodate the population on the very same land as well as make sure that sufficient land is also available for agricultural and other purposes....

there is growing concern about the quality of life in high density cities/urban areas and they need to be addressed..... here the question arises can they be addressed to make the high density cities livable and sustainable?

Compact cities in Planning refers mostly to Public Transport Oriented cities, walking cities, cycling cities Cities of short distances...where people are not dependent on Cars and everything is well accessible by Public Transport. Moreover these developments are often a 'Mix use development'. If we consider to implement these concepts to fast growing countries like India or other SA country, we need to look for strengthening existing Infrastructure which could support use of Public Transport. Pockets in between the existing development should be developed as mixed use and awareness for using Public transport or cycling or walking for short distance travel is needed. further concept of work from home could help make cities livable and sustainable. the key point would be making people more aware about climate change or sustainable living etc.

Thank you Himanshu!

I hope you find this useful

kind regards 

Article Towards an effective strategy to cope with housing land scar...

Compact city is just one attribute that leads to sustainable urban design.

i think compactness doesnt means highly dense polpulation,padestrian constraint-- but the soul is to create a sociallyrich,interactive and environmentally safe neighbour hood.

I think it can be one of the useful resolutions for making sustainable cities. compact cities by providing a comprehensive economic, socio-cultural package can reinforce sustainable factors in the city.

It depends on the condition of the city because the compact city is not suitable for all cities.

The compact city is sustainable because it offers services to citizens

Thanks a lot

The compact city protects agricultural land....

Dear Sir

Providing Urban Amenities to Rural Areas (PURA) concept given by Dr. A.P.J. Abdul Kalam is the way to check the urban growth. Similarly providing facilities in urban fringe areas/peri urban areas and exurbs may check urban growth.

regards