Uganda says it has asked China for a $500 million loan to help build almost 600 km of roads in the country's oil-rich west. This request comes amid criticism over heavy borrowing that has ballooned the country's debt. Uganda has discovered an estimated 6.5 billion barrels of crude reserves on its Albertine rift basin along the border with the Democratic Republic of Congo. However, lack of infrastructure, such as roads and an export pipeline, as well as disagreements between the government and international oil companies over taxes, have repeatedly delayed production. Uganda wants to start oil production in 2020, when a pipeline through neighbouring Tanzania is set for completion. China has extended large lines of credit to Uganda in recent years, mostly for infrastructure, including power plants, roads and an airport refurbishment.