During the UN-Habitat III conference in October 2016, the European Union, the OECD and the World Bank launched a voluntary commitment to develop a global, people-based definition of cities and settlements. This commitment will support the implementation of the new urban agenda. It will also support the monitoring and the comparison of the urban Sustainable Development goal. Several of the indicators linked to this goal are highly sensitive to where the boundary is drawn around a city.

The goal of the commitment is present a definition to the UN Statistical Commission in 2019. Two linked definitions are being tested: The degree of urbanisation and the EU-OECD functional urban area definition.

In 2017, the Food and Agricultural Organization of the UN (FAO) has joined this commitment.

In 2018, United Nations Human Settlements Programme (UN-Habitat) has joined this commitment. 

This UN-Habitat Global Urban Lecture explains why such a definition is needed: