The proposal would enshrine into law rules that Switzerland's permanent resident population — both Swiss citizens and foreigners with residency papers — must not exceed 10 million before 2050.
If the population reaches 9.5 million before then the government would take steps to limit it such as through measures on asylum, family reunification, residency permit issuance and renegotiating international agreements.
The idea, proponents say, would be to help protect the environment, natural resources, infrastructure and the social safety net from strains of population growth.