What is the biggest factor that affects the industrial structure and environmental changes?

1. Special geographical location. Yunnan is located in the frontier, and the traffic is extremely inconvenient. Sea salt with relatively low salt production costs more to transport to Yunnan. Inconvenient transportation and specific marketing policies make the production and sales of Yunnan salt industry in a monopoly state. In addition, in order to increase the income of salt courses, the government regards the salt sales of local officials in its jurisdiction as one of the criteria for assessing political achievements, which has also become one of the reasons for promoting the development of salt industry. The introduction of banks is also one of the reasons to promote the rapid development of Heijing salt industry, because the marketing scope of Heijing salt industry is two-thirds of Yunnan's land area today, and the marketing location is densely populated areas with a large demand. 2. The implementation of immigration policy is one of the main reasons for the prosperity of Heijing salt industry. On the one hand, some people with salt-making skills moved to Heijing through resettlement, which brought advanced salt-making technology to the mainland and promoted the development of salt industry in Heijing. At the same time, a large number of people entered Yunnan, which increased the demand for salt and stimulated the rapid development of Heijing salt industry driven by interests. 3. The special salt policy is also one of the reasons to ensure the rapid development of Heijing salt industry. In order to ensure the high profits of the salt industry, the Yuan, Ming and Qing Dynasties all formulated a set of production, transportation and sales systems, and promulgated strict laws on smuggling salt, which effectively controlled the production technicians of the salt industry and effectively ensured the normal operation of the salt market. 4. Continued military activities are also the reason to stimulate the production of Heijing salt industry. Salt is the main source of government tax revenue. Every time there is a war and the military pay is lost, it becomes the first choice to solve the military pay. From the Yuan Dynasty to consolidate and expand the frontier, to the Ming Dynasty when Mu Ying entered Yunnan, and to the Qing Dynasty when Wu Sangui was pacified, when there was a war and the military expenditure was insufficient, the government forced to increase the export of salt industry, which was called "sending more troops to pay silver" to meet the shortage of military pay.