Many people are either homeless or having difficulties to afford to pay the rent on their flats while many properties are left vacant.

Similarly the food that is produced worldwide is much more than the needs of the whole population of humans while many people are starving in some poor developing countries.

The main problem has roots in the mindset of competition. In fact, sustainable development of today's world requires collaboration and integration, and not competition and separation. This should be promoted by government and has to become the center of attention in educational systems around the world.

If there are many in one singular area, we need to include the private sector and provide fiscal mechanisms and incentives so that we can accelerate investment in those areas as those are at risk of causing urban decay and ultimately impact on the liveability dimensions of the area.

Aryan Shahabian you are absolutely right. People are concentrated in wrong places where is not possible to provide enough housing. And vise versa

Zaheer Allam thank you, it's a good strategy when there is at least a possibility to attract any kind of investor. But what to do when a half of a city's real estate is abandoned and derilict, but privatly owned?

If it is privately owned it is easier, as there won't be any need to engage in PPP; where this can be problematic if the legislative framework is not available for that country.

In your case, you need to understand why the private sector is not developing, and they provide the incentives tailored to their limitations. However, when providing incentives in regards to land consolidation (for example), we need to be careful not to create superblocks which will attract cars instead of encourage pedestrianisation....

Here are two papers I wrote on this:

Article Economically Incentivising Smart Urban Regeneration. Case St...

Article Attracting investment by introducing the city as a special e...

Zaheer Allam thank you very much for your suggestions!

No strategies in Romania, people think that property is ”sacred”, so the owner has all the rights. Squatting is insignificant, people only squat after a deal with the owner or they squat public buildings. The only public outrage happens when buildings that are monuments of architecture are abandoned on purpose in order to be demolished and then replaced by huge office buildings, or hotels. That happens mostly in Bucharest, otherwise there is no attention to them, except for photographic safaris.

It is a very serious problem in Brazil. The social function of cities regulated by specific laws is to house people for their development and well-being. However, the main problem is real estate speculation that occurs with private land that does not fulfill this function. One of the methods used is the taxation of progressive and cumulative taxes to the owners of these lands. What is intended to make them comply with the social function or else will pay exorbitant fines. One of the obstacles to achieving this is the effective control by the public power, which in many cases does not occur and real estate speculation happens freely.

In Nigeria, dealing with privately owned vacant and abandoned properties is complex due to owners' mindset and purpose of ownership. Many people owned properties for store of wealth for posterity. For others, as a diversionary tactics from economic crime agencies or means of preserving looted public money. Some also use properties owned to be politically relevant by influencing government's decisions through land donation to reduce compensation particularly for sitting welfare or developmental projects such public hospital, schools, etc.

For those reasons, the seemingly vacant and abandoned properties may be relative. Thus, there are two approaches for dealing with these. Firstly, more research need to be conducted into purposes of private property ownership. Secondly, a thorough and regular public enlightenment is essential on the effects of vacant and abandoned properties on the environment(hideout for criminals, security threat in neighbourhood, increased cost urban or neighbourhood governance, etc).

Dealing with abandoned properties depends on the context. In Nigeria, there is no defined strategy for dealing with the issue. As David said, in Nigeria, it is a complex issue and will depend on the purpose of the property ownership. There are large numbers of abandoned properties in Nigeria's major cities and particularly in the federal capital city. A sizeable proportion of them is not held for income generation or for real business motive. Such holdings are diversionary. They could be a store for ill-gotten wealth or a camouflage for unwholesome business dealings. Even where the properties have been developed for financial returns, the investors can afford to leave them abandoned because often, the funds invested in the projects have not been acquired through legitimate means or through due process. In such cases of abandonment, I will suggest that the state should step in to tax or acquire these properties through some legal process.

Abandonment could also be addressed through remodelling of buildings to meet current taste and demand and through reduced income expectation which may become necessary due to economic declines of cities and regions.

Overall, real estate professionals should, in collaboration with governments, address the issue of property abandonment to work out strategies for dealing with it in cities where it has become a problem.

In my PhD thesis i analyzed different strategies to deal with private owners in the context of shrinking cities in Germany. Unfortunately the thesis is in german. Maybe it will help you anyway.

Book Der Dreiklang der Eigentümermobilisierung

In states with tense situation on the housing markets there are other ways to deal with that. The state of Berlin has passed a law that sees apartment that are vacant for more than 3 month as a misuse which constitutes an offence.

But to be honest there are just a few good strategies in some cities or states. There is no general german strategy. In Germany property is sacred. So it depends on the local context, local policies and the willingness to deal with that problem.

Catalin Berescu thank you very much for your reply! Actually, I found many similarities in Bucharest and my Russian city Rostov-on-Don. Also the heritage issue is the same

José Henrique Pastorelli Junior thank you for your answer. Are those progressive taxes local or regional/national? I'm wondering if there is a common regulation for the whole country dealing with this issue

Adoga David regular public enlightenment is a very interesting point that you mentioned. Do you have examples of public discussion of this topic in your country?

Chukwuma C. Nwuba thank you very much for your answer. It's a crucial point that collaboration between different actors is necessary for creating regulations in this field

Maximilian Vollmer thank you very much for your answer, it's very useful. Do you think that a general strategy would be useful in Germany? Do you feel it's necessary to change the regulations at national/federal level?

Please, define abandoned or vacant, or abandoned and vacant. In bulgarian legislation and practices there is huge difference between these two terms and the variances to deal with these properties. This is essential for correct answers in the different regional and national circumstances.

Stefan Asparuhov yes, you are right, it is very important. With abandoned I mean properties where an owner should be defined, he is not known and doesn't care about his property. A vacant building is not in use, but an owner is known and pay all the taxes

@ Elena Batunova, according to your definition/answer and the other opinions above, there are at least FIFTEEN BASIC variations in my mind:

1. Unknown owner of the property and unknown owner of building.

2. Unknown owner of the property and unknown owner of building that is part of heritage systems.

3. Unknown owner of the property and known owner of building (who cares and pays taxes).

4. Unknown owner of the property and known owner of building (who doesn't care and doesn't pay taxes).

5. Unknown owner of the property and known owner of building that is part of heritage systems (who cares and pays taxes).

6. Unknown owner of the property and known owner of building that is part of heritage systems (who doesn't care and doesn't pay taxes).

7. Known owner of property (who doesn't care and doesn't pay taxes) and unknown owner of building .

8. Known owner of property (who cares and pays taxes) and unknown owner of building .

9. Known owner of property (who doesn't care and doesn't pay taxes) and unknown owner of building that is part of heritage systems.

10. Known owner of property (who cares and pays taxes) and unknown owner of building that is part of heritage systems.

11. Known owner of property and known, but complicated ownership of building (very often hypothesis) who do care and do pay taxes for building that is part of heritage systems.

12. Known owner of property and known, but complicated ownership of building (very often hypothesis) who don't care and don't pay taxes for building that is part of heritage systems.

13. Known owner of property and known owner of building (both doesn't care and doesn't pay taxes).

14. Known owner of property and known owner of building ( just one of them doesn't care and doesn't pay taxes).

15. A lot of known and unknown owners of properties (land or building/s) who have contradictory claims (in past or in future).

Dear Stefan Asparuhov , thank you very much for this classification. It will be useful to me since we are just starting urban policies formulation dealing with the issue of abandonment and vacancy

One measure that has been used on a modest scale in Ireland is the purchase of vacant properties using compuulsory ruchase orders for use as social housing:

https://www.independent.ie/regionals/argus/news/louth-leading-the-way-in-cpo-development-37301055.html

An idea I came across in a report by a report of the Land Reform Review Group in Scotland was the introduction of compulsory sale orders for vacant or derelict property; see section 20:

https://www.gov.scot/publications/land-reform-review-group-final-report-land-scotland-common-good/pages/52/

Dear Noel Cahill thank you very much for the useful materials!

You might want to look into the squatting regulations in the Netherlands until 2009. Under certain conditions squatting was used to pressure landowners.

Also, the current Brazilian law allows squatting under certain conditions as a tool to counteract vacancy and/or speculation.

Dear Klaas Kresse thank you very much for this interesting suggestion!

A very important problem, which is confirmed, for example, by the negative experience of privatizing unprofitable state mines in Ukraine. Even attempts to sell them for a nominal fee failed. And these are not the objects that can be "locked up". If they do not pump mine water, they pose a threat of flooding of settlements and other adverse effects.

Danylo Cherevatskyi yes, your note is very important. A lot of 'ownerless' industrial objects are dangerous and provoke or can provoke contamination and disasters. I guess we'll experience serious consequences of such ineffective privatization

Someone, the state, local authorities, should be ready to take dangerous objects for maintenance if they are abandoned by the owners. Perhaps for this you need to create special funds. And this will be the society’s fee for a “quiet sleep”.

Danylo Cherevatskyi before the state should monitor and register all such objects to understand the actual scale of the problem

Of course, dear Elena Batunova !

Danylo Cherevatskyi I just wanted to say that for our country it's a big problem and to stop ignoring the issue would be already a big step...

Taxation, may also provide pressure to use the property and if (absent) owners do not pay the tax, compulsory purchase may be used to settle the taxation debt.

The possibility to use this mechanism depends on the possibility to set local property taxes.

If empty properties create health and safety risk, there may be rules that allow to address these issues on the costs of the owners (if the owners are not willing to address themselves the issues). If the owners do not pay, capturing the property value by a compulsory purchase may be an option.