The informal sector is a large contributor to Kampala's GDP. Citizens who work in the formal sector also participate in informal activities to earn more income for their families. A public servant in Kampala, for example, may engage in agriculture in addition to working in the formal sector. Other informal fields include owning taxis and urban agriculture. The use of Kampala's wetlands for urban farming has increased over the past few decades. It connects the informal rural settlements with the more industrialized parts of the city. The produce grown in the wetlands is sold in markets in the urban areas.