By selective statistic, China has at least 400 million (30%) of population earn about 2$ / person / day.
Comparing Chinese provinces with countries: All the parities in China | The Economist
They assign Vietnam equivalents Yunnan
Not sure, Tokyo with 1.9 trillion of GDP would be compared to which area in China?
---------------------------
What are the poorest areas in China?
I read an article yesterday written by a Chinese tourist about her shocking experience in the DaLiang Shan area of Si Chuan province, which is only a few hours drive from some of the richest cities of China.
Children there walk 4 hours each day through a mountain area to go to school and go back home, and the only food they have for the day are potatoes during breakfast. Starving is daily life for them and many look like skeletons. Almost all children in that area developed malnutrition related desease.
I grew up in China, but was never aware of children in my own home country are starving due to poverty. The sad fact makes me wonder what other areas in China have this same problem.
-----
ANSWER
According to a 2011 report by The Economist, the three poorest Chinese provinces by GDP are #1 Guizhou with $3,335 per person--slightly lower than India's GDP per capita. #2 is Gansu with $4,031 and #3 is Yunnan with $4,280. Obviously,
this measure ignores income inequality within provinces, so there could conceivably be areas in Zhejiang, one of China's richer provinces, where people's income is far lower than in Kunming, Yunnan's capital city. However, overall these three provinces are China's three poorest.