Hainan Province countryside, Hainan Island, China, Asia
Hainan is the smallest province of the People's Republic of China (PRC). The name Hainan also refers to Hainan Island, the main island of the province. Hainan is located in the South China Sea, separated from Guangdong's Leizhou Peninsula to the north by the shallow and narrow Qiongzhou Strait. For centuries Hainan Island was part of Guangdong Province, but in 1988 this island became part of the newly created Hainan Province (海南省, Hǎinán Shěng). The province has an area of 33,920 square kilometres (13,100 sq mi) and is China's southernmost province. Although it comprises some two hundred islands scattered among three archipelagos off the southern coast, 32,900 square kilometres (12,700 sq mi) (97%) of its land mass is Hainan Island, from which the province takes its name. The PRC government claims territories of the province extend to the southern Spratly Islands, Paracel Islands, and other disputed marine territory. Hainan Province is the largest Special Economic Zone laid out by Chinese leader Deng Xiaoping in the late 1980s. There are a total of eight major cities and ten counties in Hainan Province. Haikou on the northern coast of Hainan Island is the capital whilst Sanya is a well-known tourist destination on the south coast. The other major cities are Wenchang, Qionghai, Wanning, Wuzhishan, Dongfang and Danzhou. Hainan, separated by the Qiongzhou Strait from the Leizhou Peninsula of Guangdong, is the largest island administered by the People's Republic of China. The area of Hainan Island (32,900 km2 (12,700 sq mi), 97% of the province) is similar to that of Belgium. To the west of Hainan Island is the Gulf of Tonkin. Wuzhi Mountain (1,840 m) is the highest mountain on the island. Hainan Island measures 155 km (96 mi) long and 169 km (105 mi) wide. Most of the rivers in Hainan originate in the central area of the island and flow radially in different directions. The Wanning River in the southern part of the island is the largest river surrounding Hainan. It is 350 km (220 mi) long. The Nandu River in the northern part of the island is 314 km (195 mi) long, and its tributary, the Xinwu River, is 109 km (68 mi) long. The Changhua River in the west is 230 km (140 mi) long, and the Wanquan River in the east is 162 km (101 mi) long. Evaporation during the dry season around the coastal areas greatly reduces the flow of the rivers. There are very few natural lakes in Hainan. There is a well-known artificial reservoir, the Songtao Reservoir, in the central-north area. Compared to most of mainland China, the air quality of Hainan is far higher. Throughout 2012, Hainan had the highest air quality in the country for 351 days. The provincial government's environmental protection campaign has taken action against a number of plants. During 2012, outdated production facilities resulted in their business licenses being revoked, and 175 cases related to illegal sewage discharge were handled. Total sulfur dioxide emissions for the province were 34,000 tons in 2012, a 3 percent year-on-year reduction. In 2011, smog emissions were reduced 6.3 percent to 15,000 tons. Hainan has a tropical moist monsoonal climate. Its annual temperature change is less than 15 °C (27 °F). The coldest months are January and February when the temperatures drop to 16 to 21 °C (61 to 70 °F); the hottest months are July and August, and the temperatures are 25 to 29 °C (77 to 84 °F). Except for the mountainous regions in the central part of the island, the daily average temperature in Hainan is above 10 °C (50 °F), and the integrated temperature during the growing season of the crops reaches eight thousand to nine thousand degree Celsius-days. The summer in the north is hot and, for more than 20 days in a year, the temperature can be higher than 35 °C (95 °F). The average annual precipitation is 1,500 to 2,000 millimetres (59 to 79 in) and can be as high as 2,400 millimetres (94 in) in central and eastern areas, and as low as 900 millimetres (35 in) in the coastal areas of the southwest. The eastern part of Hainan lies in the path of typhoons, and 70% of the annual precipitation is derived from typhoons and the summer rainy season. Major flooding occurs due to the typhoons and they can cause many problems for the local residents. From January to February, the island of Hainan is affected by thick fog, particularly in coastal areas and the northern part of the island. This is caused by cold winter air from the north coming into contact with the warmer sea, causing the moisture that evaporates from the sea to be condensed into fog.