随着非洲人口的膨胀 — — 从1960年的大约2.85亿增加到今天的近13亿 — — 以及城市化的进展，这一挑战也越来越尖锐。
As the continent’s population has swelled, from about 285 million in 1960 to nearly 1.3 billion today, and urbanization has progressed, the challenge has become increasingly acute.