ພວກ​ນັກ​ຊ່ຽວ​ຊານ: ການ​ຂະ​ຫຍາຍ ເທດ​ສະ​ບານ ຈະ​ກໍ່​ໃຫ້​ເກີດ ວິ​ກິດ​ການ ທີ່​ຢູ່ອ​າ​ໄສ ໃນ​ທົ່ວ​ໂລກ

More than half of the world's population lives in cities, according to United Nations figures. By the middle of this century, 68 percent of the world will be urbanized, adding 2½ billion people to global cities. The growth will bring problems, including lack of housing, and, as Mike O'Sullivan