Initiated in 2010 Shanghai Declaration as a heritage from 2010 Shanghai Expo, World Cities Day is so far the only international day promoted by China in the United Nations.

The World Cities Day was established on 27 December 2013 by the General Assembly in its resolution A/RES/68/239, in which the General Assembly “decides to designate 31 October, beginning in 2014, as World Cities Day, invites States, the United Nations system, in particular UN-Habitat, relevant international organizations, civil society and all relevant stakeholders to observe and raise awareness of the Day”.

The general theme of World Cities Day is Better City, Better Life, while each year a different sub-theme is selected, to either promote successes of urbanization, or address specific challenges resulting from urbanization.