The world's population is growing steadily. According to the United Nations, the world's population will grow to 9.7 billion people in 2050. By 2100, nearly 11 billion people could live on Earth. This rapid population growth is accompanied by an increased degree of urbanization. While around 55% of the world's population lived in urban areas in 2018, this proportion will rise to around 68% by 2050. Cities, therefore, face incredible problems such as environmental degradation and pollution, urban immobility, and increased energy demand.