For me, it means a city which been combined together from its history, natural environment and climate, buildings and structures, art and culture, business and industry. It leads to a strong sense of place creates a sense of belonging, in the fact, this is a dream to make people care - and this may be given attractions for creating a sustainable city.

Dear Anju

It is a difficult question.

In my modest opinion you could measure how sustainable a city is by computing its inputs and its outputs. For instance, regarding water consumption there should be a balance between drinking water supplied to the city, and the amount of treated water returned to a source

Regarding oxygen there could be a balance between what is consumed by its inhabitants and how much oxygen is produced by the green plants in the city

Regarding consumables sustainability con be measured in percentages of recycling of glass, plastic, paper.

Even in Education, there is a percentage of third level education that graduate,.

The same for fossil fuel entering the city for power generation, and the percentage it is utilized by means of generation and co-generation, house heating, waste heat used in another projects, etc.

I don't know if there are studies on computing these degrees of utilization; If there are not, I would be interesting their pursuing

Sustainability has to do with the management of change in such ways that the institutional framework, the direction of investments, the orientation of technological development, and the exploitation of resources curtail neither current nor future potential; from this exigent definition, it follows that sustainable cities provide enduring ways of life across the social, environmental, and economic domains.

PS: The idea of meeting the needs of the present without sacrificing the ability of future generations to meet their own needs—which underpins the concept of sustainability—admittedly (and inevitably) leads to much ambiguity; and so, there is a great deal of variation in terms of how some cities attempt to become sustainable.

Simple to say but difficult to apply, a sustainable city is a city whose development targets all the SDGs. This can ideally take place using LCSA frameworks to measure and monitor the impacts of the urban development and make optimal decisions. The SDGs not only take into account local conditions but they are also concerned with global and glocal scales and dynamics. As we have only one earth and all the environmental, economic and social dimensions of the human civilization is deeply and vastly interconnected and interrelated around the world, no true sustainable city may come to existence unless other parts of the world also develop on the right track of sustainability. Nevertheless, neither SDGs nor LCSA frameworks and techniques are set entirely flawless, clear, or applicable and thus there would always remain room for improving and upgrading them as well.

Dear Aryan

I agree with you but I am not sure that Sustainable Development Goals (DSG) specify concrete measures

I agree also with your mention of Life Cycle Sustainability Assessment (LCSA), and in fact I believe that current trends in many industries, for years, have been recycling no longer used products, and the percentage of recycled material is a good measure of city sustainability

Regarding what you say about that it is a global effort, of course you are right. Now try to convince countries like USA, Canada, and Western Europe to reduce their footprint!

If somebody could do that will deserve more that one Noble Prize!

For me, it means a city which been combined together from its history, natural environment and climate, buildings and structures, art and culture, business and industry. It leads to a strong sense of place creates a sense of belonging, in the fact, this is a dream to make people care - and this may be given attractions for creating a sustainable city.

I agree with the various comments. Very difficult to do, especially if you want to make it practical.

There are so many elements of sustainability that depend on individual circumstances, like the proverb of the blind men and the elephant.

Personally I would start by defining risks - their gravity and probable future frequency and then evaluate how vulnerable the city is.

E.g. with the recent disaster in Sulawesi one might imagine that a risk assessment would identify tsumani as a potentially catastrophic risk and then develop ways at least for early warning.

Sustainability means preserving the nature by using it to the need and allowing the rest for future. I go with all others by stating that achieving sustainability in a city is a big task where in in involves all aspects of planning. Planning must be done in such a way that micro planning in all aspects are need. the aspects cover - nature, socio economic aspects, finance, tradition, etc.,

Dear Nolberto Munier , Aryan Shahabian and Khalid Mohammed Breesem

Thank you very much for sharing your views.

Nolberto - I couldnt agree more that the basic principle is to measure inputs vs outputs. And yes there are studies which reflect this principle!

Aryan - You are right about the global model of sustainability and circularity, as we cannot create one city sustainable at the cost of making another more polluted and unsustainable (similar to what Nolberto is hinting at ...developing vs developed - who is the culprit debate). I would be interested to learn more about the LCSA framework from sustainable cities point of view ...

Khalid - A very pure thought indeed...sense of belonging and sense of care..but how many people actually care....even though they have the sense of belonging?

Dear Peter Baker and Latha Chinnaswamy

Many thanks for sharing your ideas.

Peter - I may need to read more on whether safety and sustainability are connected or not. I personally feel it should be though not sure!

Latha - I believe microplanning is essential but not sufficient. The consumer sensibility, education, policies, economic status etc. play a major role...

Dear Olivier Serrat ,

Excellent interpretation and definition!

Do you think there are cities around which fit under this definition. Just curious.

Anju Baroth, much as the learning organization, the sustainable city is an ideal worth striving for. The definition of a sustainable city that I volunteered is exigent, meaning, that it requires or calls for much; that said, action is best taken when objectives are smart, viz., specific, measurable, achievable, relevant, and time-bound. If it is agreed upon, that definition of a sustainable city (or of course another) would then invite measurable actions across relevant dimensions and probably have to do with the Triple Bottom Line of People, Planet, and Profit (that also frames the Sustainable Development Goals).

PS: I have not looked for cities that illustrate the definition I gave; in the absence of agreed-upon criteria, selecting this or that would be subjective.

PPS: One example of a Sustainable City Index is at https://www.arcadis.com/en/global/our-perspectives/sustainable-cities-index-2016/.

A sustainable city for me is the one that creates an environment for natural leaving and has the capacity to eliminate or minimise the degrading by-products of normal city life. Examples are like how the city should recycle it's waste to make renewable energies and create products from recyclables. A city that would use horses to collect garbage than using trucks. A city that its public transport uses electricity than using fossil fuels for energy.

Dear Sipho

I agree with most of your comments, however I don't share your opinion of coming back to using horses for collecting garbage,

Mankind have been using animals, and especially horses, since the dawn of the civilization, and causing unbelievable suffering , and then it does not call for sustainability, because respect to animals is also sustainability.

Regarding use of electricity of course I agree with you, under the condition that said electricity is produced from renewable sources

Thanks Olivier Serrat

SMART goals and objectives, as you mention are very much possible in corporate world as we all know (when it comes to chalking in the beginning of the year and assessing the performance against it at the end of the year) and wish if a task oriented manager looks after the goal of a sustainable city then that should also be very much possible :)

@ Sipho Masinga ...thanks for your post. I agree with Nolberto Munier that the public transport if electrified with renewable grid mix, will be called sustainable.

I completely agree with both of you Anju Baroth and Nolberto Munier advocating for animals is not meant to reintroduce their suffering but to complement mankind in the creating of a sustainable environment. There is a worldwide trend of re-introducing animals especially in agriculture organic farming, to create the sustainable production of food. Last time I checked, that a small town in France was using mules to collect garbage to create a sustainable town by banning trucks to decrease air and noise pollution.

What is a sustainable city is a very broad topic that takes into account environmental, economic, social, cultural and technical aspects. Trying to give a possible (limited) definition I would say a city is sustainable when it produces in a sustainable way the resources it uses, with a zero or positive impact on the global environment.

In my humble opinion the ideal would be an indicator that involves all possible sustainable indicators, something similar to the GDP that comprises many things and synthesize them in only one figure.

Not that I am saying that the GDP procedure is correct, because it is not, due to the fact that it ignores aspects such as externalities ( that is, aspects that do not have a market value, such as air contamination in the city) , and that in addition, computes as a favorable input the money spent in jails and in training people to fight crime, and many other similar aspects that should be deducted instead of added

I am just talking about the principle it works on.

Therefore, I believe that what should be done is to identify the relevant indicators that measure city sustainability, for instance disposable income, square meters of green spaces per inhabitant, the Gini Index, the Social Development Index, water consumption , recycling, housing, etc.

As a second step it would be necessary to weight each one scientifically,.

A third step would be to combine them all, because most of them are interrelated, and from there to determine a composite indicator, that can be updated each year, and in so doing showing the advance, or not, of the city from the sustainability point of view.

The three steps are feasible

The real example of a sustainable city is Freiburg in the southwestern part of Germany. The city is known as an environment protecter. Green walking paths, cycling routes, public transport station design, the participation of citizen in Designing buildings, creating spaces for social interactions among people in the environment, living without a car, designing of houses and urban areas were regarding the protection of environment, the use of rainy water and environmental energies is one part of the features of this city.

Dear Sepideh Bazari ,

Superb.. Thanks for sharing this update. We need many more such cities and the leadership to promote concept of partnership between people and environment.

I agree with Sepideh and Anju

Sustainable cities will first of all strive to reduce their ecological footprint, considering that they compulsively consume food, water, energy, etc. and practically do not recycle to create new agricultural, livestock, forest, but waste all their consumption in waste and waste, so practically never be sustainable.

@p9n3c8o

Dear Penacho

Your statement appears to be contradictory. First you speak of a sustainable city, and then you say that it is not sustainable because it never recycles. In my opinion if it is sustainable, it recycles

A sustainable city makes a euphemism derived from development, a way to accredit human depredation to the extreme without reflecting on the limits of economic growth without limits

Penacho

Development is inevitable, and it brings more consumption, but sustainable policies try to compensate for that additional consumption of resources, manufactured products, as well as land and water. They try to make a more efficient use of resources, for instance using only the correct amount of water, developing new green areas, improving recycling of everything such as water, glass, aluminium, paper and boards, by using less energy (converting street lighting from sodium and mercury to LED is an example).

Substituting packaged products by bulk, replacing old conventional energy sources by wind and photo voltaic, and even replacing old steam powered turbines in power plants by gas turbines fed with natural gas. Developing exclusive walking areas and forbidding the access of cars, promoting sharing cars, developing subways and street car networks, etc.

Promoting proper to use public transportation with electric or propane powered buses and redesigning networks to be more efficient. Building bikes lanes, etc

Using modern sewage plants for cleaning sewage and using the by products for agriculture

This is seeing reality and taking measures to address the problems

Do you think that this an euphemism?

I think that euphemism would be trying to hide the problems with words

Don't you think that cities even when they are continuously growing are not in a better condition environmental-wise as the were 50 years ago?

Sustainable City is the one which gives an Opportunity to all its population irrespective of Economical & Social status to live in leaving no negative impact on other things yet leaving scope for accommodating the inflow population with measures to rejuvenate itself by adopting positive technological innovations for enhancement of quality with lesser resources and with a belief in basic tantrums of Humanity "LIVE &LET LIVE" i.e. conservative attitude of consuming what is Needed and not Desired.

Perfect explaination Dr. Tata V S Rao !