The United Nations Children’s Fund, commonly known as UNICEF (联合国儿童基金会), reported that almost 500 million children, mostly in West and Central Africa, have to stay in places where it’s hotter than 35 C for more than half of the year. This is quite harmful (有害的). UNICEF said that young bodies heat up faster and cool down more slowly. The extreme heat (酷热) makes it easier for them to fall ill. So countries and regions must act fast to solve the problem, Catherine Russell, executive director of UNICEF, told Xinhua.