Around 55% of the world’s population – or 4.2bn people – lived in urban areas in 2018, up from 47% in 2000, according to the UN. Because of the rapid rate of urbanisation, this figure is expected to reach 68% by 2050, with growth concentrated in Latin America, the Middle East and North Africa (MENA), sub-Saharan Africa and Asia. The shift towards the cities put the onus on the...