According to Transparency International's Corruption Perceptions Index 2013, Denmark and New Zealand have very low levels of perceived corruption just as they did last year. Afghanistan, North Korea and Somalia are perceived as highly corrupt. This year's index ranks 177 countries and territories by their perceived levels of public sector corruption.

DW: Why are countries like Denmark, New Zealand and the Scandinavian countries so successful?

Alejandro Salas: Great part of the countries' success that score better is they are not only putting in place the infrastructure for fighting corruption and for promoting transparency, they are actually putting it into practice. You can have a situation for example in a city where you promote the use of stop lights in every corner, so you have stop lights to control the traffic. But if you have this infrastructure, but you don't have a reliable police force that will stop you if you cross a red light, then it's up to the person to decide if they are going to stop or not.

The same happens with anti-corruption. You can have infrastructure: you can have laws, you can have institutions. You can have all sorts of commitments with the international community or codes of ethics in the case of business. But if you don't take them into practice, nothing happens. I think the big difference with the countries that are scoring high is that they have the political will and they enforce the laws and the infrastructure they have in place.

Which countries have improved on the Corruption Perceptions Index this year compared to last year's ranking and why?

The fact that a country scores higher or lower in the index doesn't mean necessarily that the country is more corrupt. It's a perceptions index. Now, the countries that have improved the most according to the Corruption Perceptions Index are Myanmar, Laos, Senegal, Brunei - all of those have gone up five or six points. And then you have also a group of countries that have gone up by four points including some European [countries] like Estonia, Greece and Latvia. And you also have Lesotho in that group.

Can you explain why? What are the reasons for their rise?

There would be different explanations in each case. But I was particularly paying attention to the case of Greece. It's interesting because Greece has frequently been the last place among the European countries in this ranking. And we know there have been a lot of scandals; there has been the financial crisis. And I think Greece in a way touched one of the lowest points last year in terms of perception of corruption. And one very important thing is that the Greek government has taken action in promoting laws and promoting initiatives to counter the problem.

The political message that is being sent by the Greek authorities has been very important. However, the challenge remains to see if all these commitments and these new laws are going to be used. They are raising expectations. So let's see what happens in the next one, two or three years.

But even though Greece has moved slightly closer towards the spectrum's "clean" end, it still only scores 40 out of 100, sharing its rank with China. So there is quite some room for improvement, isn't there?

Yes, absolutely. And in the case of Greece, they shouldn't be celebrating. They are still below the [average], but I think as an international community we need to encourage that, we need to welcome that, we need to keep up the pressure from civil society and from the citizens of Greece for these changes to really happen in practice.

And which countries have received a lower rank on this year's index and why?

Syria has fallen more which is sad, but it doesn't surprise me. They have been in this bloody and violent civil war, it's of course obvious that the institutions are not working properly. There are groups in power close to the governing family that are taking charge of the ministries. And, as you can imagine, the procurement systems and the contracting systems and all of these things in Syria aren't working because of the war. And these are the entry points for corruption.

If you have a look at the list of 177 countries on the Corruption Perceptions Index, the ones that are at rock bottom are Somalia, North Korea, Afghanistan, Sudan and South Sudan, Libya, Iraq. As long as they don't recover strong institutions, the systems to prevent corruption are not in place.

Countries like Syria, or the Gambia or Libya, Mali - these countries are all countries where you wouldn't be too surprised that they end up where they did. But with countries like Spain or Australia it's quite surprising that they received a lower rank compared to last year's index.

Spain is the one that changed the most after Syria [compared to last year's figures]. And this doesn't surprise me, because in the last three years, we have seen Spain making headlines with corruption scandals. And it's not only about the corruption scandals, because this could probably be a reflection that they have a very open and free media.

But when one looks at the corruption scandals, you can see a lot of structural problems behind them. The whole issue of land procurement, construction permits, the whole infrastructure for building and property ownership and all of this has been a huge problem in Spain costing millions and millions of euros. The lack of accountability mechanisms and the way the political parties moving their finances and these scandals have even reached the royal family. So in a way, Spain's scandals, structural problems, no punishment is like a perfect recipe for going down in the perception index.

In Africa, Senegal and Lesotho have improved while the Gambia, Guinea-Bissau and Eritrea have not. In Europe, Greece, Estonia and Latvia have improved, but Spain for instance didn't. So there is no overall global tendency that corruption levels are rising or seeing a decline?

No, but you can draw some conclusions that are not necessarily geographic. When you look at those countries that are - according to the United Nations definitions - among the least developed countries in the world, they went down by one point. It's not a huge change, but it sends an important message.

Another important trend that I'm observing - it's in a small region but I think it's interesting - is in Central America. When you look at the six countries in the region, all of them went down. In some cases, by four points, like Guatemala, in some cases by one point like Nicaragua. It's interesting to see that it's almost similar to what is happening in Syria or in countries with war.

When you look at a region that has been affected by violence and captured by organized crime - as Central America is - you can see that there is a trend downwards. Because organized crime in order to be able to do business, you need corruption. You need to pay bribes to the police, to the military, to the customs officials, to port authorities. So organized crime is one of the main interest groups that want to weaken institutions.

We increasingly see that countries that used to be very peaceful like Costa Rica, Panama, are starting to be part of the drug route and are starting to be places captured by organized crime. We can see that institutions are getting weak. This is something we can also start seeing in places like West Africa or in other regions where violence and crime and organized crime are taking a very deep root.

What can be done to effectively curb corruption?

We need to exercise pressure; we need to show that corruption is a negative value. There's a recent example from Paraguay. It was discovered that a senator was giving jobs to his former nanny, a former beauty pageant contestant and some family members and they have positions in the government and in parliament. There was a vote in the senate to remove the senator's immunity, but his friends, the senators from his party, voted for not lifting that immunity.

The people in the streets were furious. Places like restaurants, pizza joints, gas stations, many, many commercial places put a list in their doors saying 'I don't serve corrupt people' - and they put the names of the twenty something senators that were supporting this corrupt senator and they didn't provide service to them and their families.

It was amazing, because with that pressure, by saying no to corruption, not only complaining, but actually taking action, the senate finally decided to lift the senator's immunity. So the social pressure worked. Not in a violent way, but by not allowing corruption. I think that's a very important change we all can do.

Alejandro Salas is the Director of Transparency International's Americas Department.