China's urbanization mustard index

"Chinese officials, charged with moving 250 million rural farmers into cities over the next decade under the central government’s sweeping“National Plan for 
Promoting Healthy Urbanization (2011-20),
”have developed a “pickle index” for measuring the movement of migrant workers."
"...found that sales of zha cai, a pickled mustard tuber, provide a better guide to population flows than often unreliable provincial statistical data."
"This ebb and flow of pickle sales from the megacities of Guangdong to the more rural northern provinces suggests that migrant workers are returning home en masse, which could signify either a national slowdown in urbanisation or — as the NDRC hopes — a shift in the geography of growth, away from Shanghai and Guangzhou and toward “second-tier” cities in China’s interior."

the pickle as the carrot. flock like the birds.

via ediblegeography