Why do some people divide Jiangsu people into people in northern Jiangsu and people in southern Jiangsu?

Jiangsu is divided into northern Jiangsu, central Jiangsu and southern Jiangsu according to geographical and cultural traditions. Five cities in northern Jiangsu: old northern Jiangsu (before the mid-1990s)-Xuzhou, Lianyungang, Huaiyin, Yangzhou and Yancheng; New Subei-Xuzhou, Lianyungang, Huai 'an, Suqian and Yancheng (Suqian was newly established in the 1990s, Huaiyin was renamed Huai 'an, and Yangzhou was placed in the middle of Jiangsu). However, the territory of Jiangsu will change greatly in the next few years. Four cities in northern Jiangsu were separated from Jiangsu and restored to Huaihai Province and Xuzhou, the provincial capital, together with several cities in southern Shandong, southern Henan and northeastern Anhui. Part of southern Jiangsu will also leave Jiangsu and form a new Jiangsu and Zhejiang province with Nanjing as its capital.

Nanjing is the boundary, Suzhou and Wuxi are often in southern Jiangsu, and the rest are in northern Jiangsu. One way is to divide the areas outside Suzhou, Wuxi and Changzhou into central Jiangsu and northern Jiangsu.