Why does Jiangsu Province need to divide a new central Jiangsu besides the original division of southern Jiangsu and northern Jiangsu?

In fact, there is no clear division between the Soviet Union and China. Just as Nantong, Yangzhou and Zhenjiang are close to the Yangtze River basin (separated from southern Jiangsu by only one river), their economic development is indeed better than that of the northern cities Huai 'an and Xuzhou, so people have the consciousness of calling them Central Jiangsu. But for most people, it is northern Jiangsu, because it is north of the Yangtze River.