Research on
specific cities and products yield data like the following: in Hanoi, 80 % of fresh vegetables, 50 % of pork, poultry and fresh water fish, as well as 40 % of eggs, originate from urban and peri-urban areas (Nguyen Tien Dinh, 2000); in the urban and peri-urban area of Shanghai, 60 % of the city's vegetables, 100 % of the milk, 90 % of the eggs, and 50 % of the pork and poultry meat is produced (Cai Yi - Zhang and Zhang Zhangen in Bakker et al. 2000); in Java, home gardens provide for 18 % of
caloric consumption and 14 % of proteins of the urban population (Ning Purnomohadi 2000); Dakar produces 60 % of the national vegetable consumption whilst urban poultry production
amounts to 65 % of the national demand (Mbaye and Moustier 1999).