Interior ministers of the European Union are convening in Brussels on Thursday to discuss approving the passport-free travel Schengen Area membership for Bulgaria, Croatia, and Romania.

There are two draft decision on the agenda of the two-day meeting of the Justice and Home Affairs Council, and one is about Croatia’s admission to the passport-free zone and the other is about the admission of Bulgaria and Romania.

The Schengen Area includes 22 EU countries plus four non-EU nations (Iceland, Norway, Liechtenstein, and Switzerland). A unanimous decision by the 22 current members is needed for new approval of new bids.

European Union countries which are not part of the Schengen Area include Cyprus, Ireland, Romania, Bulgaria, and Croatia. Out of these five, only Ireland had negotiated an opt-out from the system when they joined the bloc in 1973. The remaining four, who joined between 2004 and 2013, are obliged to join the area some time in the future.

Schengen membership means removing all land border controls between member countries while at the same time reinforcing external EU borders with non-EU countries, essentially allowing nationals of member countries free travel without any passport or customs checks.

Croatia is expected to be given the go ahead on Thursday, although there is reportedly still no agreement on Bulgaria and Romania. Austria is currently objecting to their admission, due to the increasing influx of illegal migrants across the so-called Balkan route. The Netherlands, on the other hand, supports Romania’s membership but opposes Bulgaria’s admission.

The Czech Republic, which currently chairs the rotating six-month presidency of the EU, has prepared drafts proposing that Romania could be admitted in October 2023. As for Bulgaria, they propose a new assessment in July 2023, which would pave the way for both countries to finally join in 2023, some 16 years after joining the EU in 2007.

If approved on Thursday, Croatia is expected to join on 1 January 2023.

Billed as one of the main achievements of the European project, the Schengen Area is the world’s largest border-free travel area. It is named after the village of Schengen in Luxembourg, on the border tri-point between Luxembourg, Germany, and France, where two agreements on on free travel creating the area were signed in 1985 and in 1990.

The Schengen Area today includes about 4 million square kilometers with a population of almost 420 million people. It is estimated that every day around 3.5 million people cross internal EU borders for work or study or to visit families and friends, and there are close to 1.7 million Europeans residing in one Schengen country while holding a job in another.