Switzerland currently has a population of just over 9.1 million. But the largest party in parliament, the right-wing populist Swiss People's Party (SVP), does not want to see the population grow further and has collected enough signatures to push through a referendum in June.
To keep the population down, the proposal would introduce strict restrictions on asylum seekers and residence permits once the population exceeds 9.5 million.
Critics - virtually all other parties in parliament - believe the initiative would have devastating consequences for Switzerland's relations with neighboring countries such as Germany and France, from which many people with residence permits come.
