Assu is 16 years old. The young Burundian lives in the Brussels transit center for migrants. Like many of his compatriots, he took advantage of Serbia's visa-free travel policy to reach Europe — hoping for a better life.

"I arrived in Serbia at night, and the next morning I went to a place where there were smugglers," Assu said, recalling the perilous journey that eventually led him to Belgium.

"They helped us get from there to Bosnia. Everyone had to pay €250 ($247) if they wanted to get from one country to another."

Escape: Dangerous Balkan route

The Balkan route is risky and expensive: Refugees have to pay up to $3,000 to reach their final destination, DW learned from migrants, many of whom have crossed Bosnia, Croatia, Slovenia, Italy, Switzerland, and on to Germany or France before arriving in Belgium.

Assu chose to travel to Brussels — home to a large community of Burundian migrants and asylum seekers. His journey to the Belgian capital was a traumatic one, he said.

He was on the road for weeks with a group of young people, hiking through forests and over rough terrain, sleeping in abandoned buildings, while enduring severe cold. "When you are left behind on the trail, you are left behind," Assu told DW.

"When we arrived in Croatia, we were beaten up by the Croatian police before they allowed us to enter their country," he claimed.

"We persevered. When we arrived in Slovenia, we were walking on the train track, and I saw the bodies of several people who had been left there. I just stepped aside. It was scary." 

Asylum application: Waiting for hearing

Assu is still waiting for a hearing. Belgium has been overwhelmed with processing asylum applications since the increased arrival of Syrian, Afghan and — more recently — Ukrainian refugees.

There is a shortage of accommodation, food and legal aid, refugees told DW.

The Belgian Federal Agency for the Reception of Asylum Seekers acknowledged these shortcomings. Despite the establishment of thousands of transit centers, their capacity is insufficient. As such, women, children and unaccompanied minors are given priority.

The many asylum seekers who are unable to find shelter have no other option than to sleep rough in the heart of the European capital.

Tony — who has been living in the park near Brussels North train station for two months — is no exception. Now he's worried about the upcoming cold winter weather. 

"I am here because I have many problems in my country, including fear for my safety. I want to continue my professional career in Brussels," Tony told DW.

He has not yet been invited to any hearings and is only allowed to stay in the park, Tony said. Every now and then, aid workers come by. He continues to hope for a place in the reception center.

Greater push into the EU

Burundi is one of the world's poorest countries. UN agencies have also reported human rights abuses and violence against civilians. The population is facing a humanitarian crisis marked by economic collapse, extreme food shortages and outbreaks of disease.

More than 228,000 "irregular" migrants entered the EU in the first nine months of 2022, according to Europe's border agency Frontex. That's a 70% jump on the same period last year. 

The Balkan route accounted for the largest share, with more than 106,000 entries. Most of the migrants come from Syria, Afghanistan, Turkey, India, Cuba and Burundi.

Swedish politician Ylva Johansson, who serves as the European Commissioner for Home Affairs, deplores the situation.

"We have seen a significant increase in the number of migrants on the Balkan route, and we also see especially those who travel without visas to the countries of the Western Balkans, including to the area of the European Union. And that, of course, is something that worries us," she said.

Criticism of visa-free regime

Serbia is one such gateway for migrants. German Interior Minister Nancy Faeser made it clear that she did not think much of Serbia's visa policy. This, she said, is based on which states do not recognize Kosovo. She finds this "unacceptable." 

In fact, Serbia's visa policy is closely linked to its claim to Kosovo, which is almost exclusively inhabited by Albanians.

Belgrade retaliates against countries that do not recognize or have withdrawn their recognition of this former Serbian province, which has been independent since 2008.

Burundi withdrew its recognition of Kosovo in 2018. In response, Serbia abolished its visa requirements for Burundians.

Serbia-based political analyst Jaksa Scekic regards the country's visa waiver for some African countries as a reward for their political stance as problematic.

"When the EU realized this, it threatened Serbia to reintroduce visa requirements for its citizens if refugees kept coming," Scekic said.

Serbia bows to EU pressure

On October 21, the Serbian Foreign Ministry announced that travelers from Burundi and Tunisia would henceforth have to apply for a visa to enter the country.

"All these poor people will try to emigrate to the EU," Scekic told DW.

"Serbia is a transit country. These people don't want to stay here. They don't want to work here for €500 a month, they want to work in the EU for €2,000."

Nikola Kovacevic, a Serbian lawyer and refugee activist, stressed that "on the one hand, Serbia has the sovereign right to make visa arrangements with any country according to its own interest. But Serbia is not able to control the migration flow that comes with it."

The consequences, he said, can now be seen, not only in Serbia but in many EU member states.

Eric Topona, Ubena Bakari and Idro Seferi contributed to this article.