What is the reason why Chongqing became a municipality directly under the Central Government?

Pure personal understanding: 1. The Three Gorges Project will cause a large number of reservoir migrants, most of whom will come from the Sichuan side of the Three Gorges area (East Sichuan), which will make the already poor East Sichuan even poorer and increase the burden of Sichuan Province. Even with the support of the central government, it will be quite troublesome. Sichuan has been trying to get rid of this burden. The central government is considering directly supporting (or managing) the reservoir area, which leads to the possibility of establishing a new provincial administrative region. If we want to establish a municipality directly under the central government, we must find a vibrant city as the core. There are two choices: one is Yichang, Hubei, which is also in the reservoir area, and the other is Chongqing in eastern Sichuan. Chongqing is bound to be the first choice. Chongqing has a good industrial base, a planned city, various transportation hubs in the southwest, and the top of the reservoir area just reaches old Chongqing. In addition, the whole eastern Sichuan (including Chongqing) has a high similarity in folklore, geography, language and culture (compared with Chengdu Plain, the difference is quite large). 4. Therefore, Chongqing has become the core to support the development of the reservoir area. In addition, the wife of former premier Li, one of the leaders of the Three Gorges Project, is from Chongqing, and former premier Li himself also goes to school in Chongqing. Personal emotional factors may also have a considerable component.