The city consists of two disputed island chains (the Paracels and Spratlys, known in Chinese as Xisha and Nansha Islands, respectively) and a submarine atoll.

The Ministry of Natural Resources released an updated city map on Sunday, showing the labels of Xisha and Nansha districts, which were established in 2020 but were not included in previous maps.

Sansha, part of the southern island province of Hainan, was founded in 2012 to assert China’s claims to the resource-rich South China Sea.

The Ministry of Civil Affairs also assigned administrative district identifiers to the two districts. These codes are used to identify places for census and administrative purposes and generally appear as the first six digits on the identity cards of residents born and registered in an area.

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History, money and military: Why is the South China Sea so important to Beijing?

History, money and military: Why is the South China Sea so important to Beijing?

Separately, China Post announced on Sunday that the city’s Nansha district has been given postal codes, while three inhabited islands in the Xisha district – Woody Island, Tree Island and Jinqing Island – will continue to use their own codes.