Why is it necessary to restrict regional hukou in high school?

In order to prevent college entrance examination immigrants! —— The National College Entrance Examination in Yunnan Province (hereinafter referred to as the "College Entrance Examination") requires (1) registration. 1. Persons who meet the following conditions can register: (1) Abide by the Constitution and laws of People's Republic of China (PRC); (2) graduated from a senior secondary education school or equivalent; (3) good health; (4) My household registration and my father's (or mother's) permanent residence are in our province, and I have been in high school for three years in our province. 2. The following persons are not allowed to register: (1) students in institutions of higher learning with higher education; (2) Students who have not graduated from senior secondary education schools this year; (three) because of the violation of the criminal law, the relevant departments have taken compulsory measures or are serving sentences; (4) Ordinary high school graduates have not obtained the Certificate of Physical Education Standards for Middle School Students in Yunnan Province; (5) The permanent residence is not in our province-the so-called college entrance examination immigration means that parents or relatives want their children to be admitted to a better university in the college entrance examination, so they take their children's household registration and student status to a province with relatively low admission scores before the college entrance examination. In this way, children studying in general provinces will be ranked in advance in the college entrance examination in special provinces, thus being admitted to first-class universities. At present, the immigration of the college entrance examination is explicitly prohibited by the Ministry of Education. After students sign up for the college entrance examination and before graduating from college, all insiders can report it. But the real cause of college entrance examination immigration is the geographical discrimination formulated by the Ministry of Education, which will be abolished in the near future! Therefore, many NPC deputies now suggest canceling the household registration system for college entrance examination, but the response is mixed. -I'm from Weihai, Shandong Province, and we don't allow it here, so many students from the three northeastern provinces have to change their hukou to study here, and their admission scores for the college entrance examination (the three northeastern provinces are 6.7 points lower than ours! ~ ~ ~ ~ Answer finished