Мбужи-Майи: Город над алмазными приисками Конго.

Mbuji Mayi or Mbujimayi (formerly Bakwanga) is a city and the capital of Kasai Oriental Province in the south central Democratic Republic of Congo. It is thought to be the second largest city in the country, after the capital Kinshasa and ahead of Lubumbashi, Kisangani and Kananga, though its exact population is not known. Estimates range from a 2010 CIA World Factbook estimated population of 1,480,000 to as many as 3,500,000 estimated by the United Nations in 2008. Mbuji Mayi lies in Luba country on the Mbuji Mayi River. The name Mbuji Mayi comes from the local language, Tshiluba, and translates as "Goat Water," a name deriving from the great number of goats in the region. Despite its large population, the city remains remote, having little connection to surrounding provinces or to Kinshasa and Lubumbashi. However, Mbuji Mayi is the traditional centre of industrial diamond mining in Congo, with it being located on top of one of the largest known deposits in the world. Air travel is provided through the Mbuji Mayi Airport.

Mbuji Mayi is made up of five communes (municipalities), each headed by a burgomaster: Bipemba, Dibindi, Diulu, Kanshi and Muya. This division into communes has been in effect since Ministerial (Departmental) Order No. 83 of March 4, 1968 of the Minister of the Interior.

The region where the city of Mbuji Mayi now stands was once a cluster of villages on land owned by the Bakwanga clan. Diamonds were first discovered in the area as early as 1907, but the true value of the find was not recognised until 1913. Following the discovery, a mining camp designed to house miners and company officials of the Societé minière de Bakwanga (MIBA) was developed in the area. The young city, known at the time as Bakwanga, grew quickly but around strict planning by MIBA, which divided the community into labor camps, mining areas and living quarters. The city's growth was not explosive, and planning was done with the needs of the mining company in mind, not the development of the region as a general population centre. In fact, fearing theft of the company's diamond resources, the MIBA actively discouraged building in the region and closely monitored who went in and out of the region. Every person in the region needed a permit allowing them to be there, and registration at a command post that monitored the population, which made indefinite residence in the area almost impossible to establish. There was limited economic activity besides the company run mining, with even limited agriculture, and the city's population remained low, at approximately 39,830 by the late 1950s. As the city grew, more and more infrastructure needs required investment in roads, public works and hospitals. While several primary schools were developed for workers, until independence, there was no higher education available for the native population. The city was constructed on top of the diamond deposits, and while the city's reputation as a company town under tight control of Belgian economic interests meant it was neat and orderly, it also meant that the city's buildings and homes, including those of top MIBA executives, were sometimes demolished to access the diamonds. The celebration was short lived, as the central government's Armée Nationale Congolaise (ANC) troops took control of the town and arrested Kalonji, by December 1961. After escaping from the jail in which he was being held, he briefly re established his government. A second assault on the independent state was launched in the summer of 1962, with ANC government troops fighting poorly armed tribesmen outside of the city. Kalonji was captured again on 4 October 1962 when ANC forces retook Bakwanga, effectively ending the region's independence. Soon after the end of the secession, Bakwanga was renamed Mbuji Mayi after the local river in an attempt to signify a Luba intra ethnicity reconciliation.

Throughout the 1980s and 1990s, Zaïre and Mobutu paid little attention to Mbuji Mayi, offering almost no money to build roads, schools or hospitals. In the political vacuum, MIBA stepped in. In the place of the federal government, MIBA invested heavily in the region by repairing roads, paying soldiers and supplying water and electricity to the city from its own power station. The company set up a social fund of $5 to $6 million a year, roughly 8 percent of its annual budget. This money went to repair infrastructure and to fund a new university. The investments and its position as largest employer made Jonas Mukamba Kadiata Nzemba the chief executive officer of MIBA one of the most powerful men in the region, and the de facto governor of Mbuji Mayi. Nzemba, who was appointed by Mobutu in 1986, was considered one of the more powerful players in Mobutu's political party, the Popular Movement of the Revolution (MPR), but he also called himself a "brother" of Étienne Tshisekedi, a popular local political figure and Mobutu's most significant political opposition. Nzemba is credited with creating the Conference pour le Developpement Economique de Kasai Oriental (CDEKO), a regional economic development group in the early 1990s. Nzemba also backed the creation of the University of Kasai, which was jointly sponsored by MIBA and the local Catholic Church, and which became the home base of CDEKO. The new organization spearheaded economic growth in Mbuji Mayi, helped support the development of new agricultural and beer industry expansion around the city and launched Wetrafa, a locally owned airline.

As the First Congo War broke out, Nzemba initially sided with Mobutu against the rebels led by Laurent Désiré Kabila, but as Kabila's Alliance of Democratic Forces for the Liberation of Congo Zaire (AFDL or ADFLC) approached the city, Nzemba quickly switched sides. When the city fell to the rebels on April 4, 1997, looting by both sides took a toll on the city, particularly MIBA's mining operations. Nzemba was also summoned to Goma to speak with Kabila, who held him for several days, prompting his family to purchase advertising in newspapers publicising their concerns for his safety. Nzemba was released shortly after, but MIBA began making "voluntary contributions" to Kabila's war, an estimated $5.5 million in 1997 and 1998.

As of 2019 some residents were obtaining water from local rivers which contributed to local outbreaks of water borne diseases such as cholera. In 2020 the DRC government launched a project to improve drinking water expected to cost at least $26.2 million. This investment was expected to help, but not be enough to substantially solve the city's water crisis. The Pan China company doing the work will rehabilitate the city's pumping station, extend the distribution network, construct water towers, and add metering and administrative buildings.

As a commercial center, Mbuji Mayi handles most diamond mining, panning, and production in the Congo. Societé minière de Bakwanga and Diamant International are the major diamond producers in the area. The city had always been a major source of the world's diamonds and that did not change after independence, nor did the age old tradition of diamond smuggling. But after independence, that ability of the government to control the diamond smuggling quickly eroded and diamond smuggling dramatically increased. The CDC investigated and found the prison was filled to six times its capacity giving each prisoner a fixed spot less than about in a cell. About half of the inmates were malnourished. These conditions, combined with poor ventilation, lack of sunshine, and lack of TB screening, had allowed TB to spread for years. Amnesty International published a report in 2002 about dozens of people being shot dead in the diamond fields of Mbuji Mayi, with most victims suspected of illegal mining. No state agents were known to have been prosecuted for the killings. Poverty lures in illegal miners to MIBA diamond concessions where they may be shot or detained in quarters with poor living conditions.

Köppen Geiger climate classification system classifies its climate as tropical wet and dry (Aw).