This week’s episode of the Lid Is On comes to you on World Cities Day, which it's hoped will foster cooperation among countries in meeting the challenges of urbanization, and contribute to sustainable development of cities and big towns everywhere.

For many years, the world has seen an inexorable movement from rural areas to urban centres, as people search for jobs, access to services and generally improved life prospects. However, many large cities have become hotspots of inequality and exclusion, a problem that has grown since the 1980s.

The UN has been trying to combat this trend, launching global campaigns and initiatives to bring about fairer cities.

Conor Lennon took a trip out the door of UN Hedquarters in New York,  to see how community gardens have become one effective and low-cost way to build stronger neighbourhoods.