Many poor urban households are active in local production of food and related activities (e.g. food processing and street vending of food, compost making, supply of animal feed). Some of these poor urban and periurban producers are mainly interested in producing food for their own household consumption, to save some cash that would otherwise be used to buy food (poor urban households often spend more than 50 per cent of their cash income on food) and to earn some additional income from occasional sales of surplus production. Others produce vegetables, herbs, fruits, mushrooms, eggs, milk, ornamental plants, etc., for sale on the urban market as a main source of income for the household. A comparative advantage for the urban producers is their close proximity to the urban consumers.