Haikou (simplified Chinese: 海口; pinyin: Hǎikǒu), situating at the north of Hainan island, is the capital of Hainan Province of the People's Republic of China. The approximate population is 830,192 (2006), therefore by far, it is the largest city on the island.

Haikou originally served as a port for Qiongshan, the ancient administrative capital of Hainan island. In the 13th century Haikou was fortified as a military post governed by the Ming dynasty (1368–1644). The port is located in the west of Nandu river outlet. Qiongshan was opened as a foreign trading city because of the Treaty of Tianjin (1858). In 1926, Haikou overtook Qiongshan in population ,and after the 1930s it was declared a separate administrative county.

Since 1949, Haikou has maintained its position as Hainan's main port, handling more than half of the island's trade. It has replaced Qiongshan as the island's administrative capital. Haikou got the capital of Hainan Province, founded in 1988.

The Old Haikou (the oldest area of Haikou) was mostly built by the rich Chinese from the mainland and some overseas Chinese who returned to their homeland. The buildings’style mixed with Portuguese, French and Southeast Asian style. These streets used to be divided into areas for medicine, silk and clothing, agricultural products, stationery, etc.

Various projects are take measures to preserve these historical buildings.

Haikou has an area of 2,304.84 square kilometers.It is situated on the north coast of Hainan Island, facing the Leizhou Peninsula, across the Hainan Strait (15 km wide).The district of Haidian island is separated from the main part of Haikou by the Nandu river. It is the northernmost part of Haikou, and there are three bridges to access Haidian Island , the largest one is Haikou Century Bridge that connects Guomao district with Haidian island.

The city of Haikou is on the northern edge of the torrid zone, and is part of the monsoon tropical zone. April to October is the active period for tropical storms and typhoons; most occur between August and September.May to October is the rainy season with most rainfall coming in September.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year
17.5	18.5	21.4	24.8	27.4	28.3	28.5	27.9	27.1	25.0	22.1	19.0	23.0

Average rainfall (mm):

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Year total
22.8	32.2	46.2	96.9	177.3	209.8	200.5	211.6	278.4	178.1	90.2	41.8	1591.5

Haikou’s air quality index is the second highest one in China, which is only second to Kunming.

The groundwater is of international standard, and is classified as mineral water.

In 1995, the Haikou city government began an initiative to improve residents’ living quality .With the approval of the World Health Organization, and China's Ministry of Health, a ten-point plan was undertaken to address such issues as:

• Community health care
• Vaccinations for children
• Waste recycling
• Green belts and urban trees
• Environmentally friendly construction
• Public toilets
• Sewage treatment
• Communications
• Noise pollution

By 2004, the city had established 43 new community health service centers covering 85 percent of the population. The initiative has increased the size of Haikou's green spaces to 2,000 hectares, with trees lining 40 percent of its roads. Noise pollution has dropped from 61.1db to 58.2db. 300 public toilets have been built. All industrial effluents, industrial waste water and solid waste, and all live sewage, is now processed through centralized treatment centers, and is disposed of without environmental impact. These improvements and others have increased life expectancy in Haikou to 78.26 years.

Haikou city has also built 163 model ecological villages. Now, over 200,000 villagers in 933 villages have tap water in their homes.

The GDP per capita was $3,573 USD in 2008, ranked number 43 among 659 Chinese cities.

Haikou exports great quantities of agricultural produce and livestock. There is a small amount of industry, including canning, textiles, rice hulling, and light industry.

Haikou received 4.11 million tourists in 2002, up 7.99 percent from 2001. The city earned approximately three billion yuan (361 million US dollars) from the tourism industry during that period, up 11 percent from the previous year.

Longhua District

Xiuying District

Qiongshan District

Meilan District

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