the bitter orange to Seville from East Asia via Iraq around the 10th century to beautify and perfume their patios and gardens, as well as to provide shade. The flowers of the tree are a source of neroli oil, commonly used in perfumery and in skin lotions for massage. In 2021, the municipal water company, Emasesa, began a pilot scheme to use the methane produced as the fruit ferments to generate clean electricity. The company plans to use 35 tonnes of fruit to generate clean energy to power one of the city's water purification plants. Economy Seville is the most populated city in southern Spain, and has the largest GDP (gross domestic product) of any in Andalusia, accounting for one-quarter of its total GDP. All municipalities in the metropolitan area depend directly or indirectly on Seville's economy, while agriculture dominates the economy of the smaller villages, with some industrial activity localised in industrial parks. The Diputación de Sevilla (Deputation of Seville), with provincial headquarters in the Antiguo Cuartel de Caballería (Old Cavalry Barracks) on Avenida Menendez Pelayo, provides public services to distant villages that they can not provide themselves. The economic activity of Seville cannot be detached from the geographical and urban context of the city; the capital of Andalusia is the centre of a growing metropolitan area. Aside from traditional neighbourhoods such as Santa Cruz, Triana and others, those further away from the centre, such as Nervión, Sevilla Este, and El Porvenir have seen recent economic growth. Until the economic crisis of 2007, this urban area saw significant population growth and the development of new industrial and commercial parks. During this period, availability of infrastructure in the city contributed to the growth of an economy dominated by the service sector, but in which industry still holds a considerable place. Infrastructure The 1990s saw massive growth in investment in infrastructure in Seville, largely due to its hosting of the Universal Exposition of Seville in 1992. This economic development of the city and its urban area is supported by good transportation links to other Spanish cities, including a high-speed AVE railway connection to Madrid, and a new international airport. Seville has the only inland port in Spain, located from the mouth of the River Guadalquivir. This harbour complex offers access to the Atlantic and the Mediterranean and allows trade in goods between the south of Spain (Andalusia, Extremadura) and Europe, the