Why did Tianjin become a municipality directly under the Central Government?

Tianjin becoming a municipality directly under the Central Government is the need of the capital. In 1913, Tianjin became the capital of Zhili Province. In June 1928, Tianjin was changed to a special city. In July of the same year, Zhili was renamed Hebei. The provincial capital was still Tianjin. In October, the provincial capital was moved to Peiping. In June 1930, Tianjin was changed to a municipality directly under the Central Government. In October of the same year, the capital of Hebei Province was moved to Tianjin and became a municipality under the jurisdiction of the province. In June 1935, the capital of Hebei Province was moved to Baoding, and Tianjin was changed to a municipality directly under the Central Government. After Japan surrendered in August 1945, Tianjin remained a municipality directly under the Central Government. On January 15, 1949, the Chinese People's Liberation Army liberated Tianjin and classified it as a municipality directly under the Central Government of the North China People's Government. On October 1, the People's Republic of China was founded. At that time, Tianjin was the most developed city around Beijing and the gateway to the sea from Beijing, so it was designated as a central municipality. However, Tianjin's economic capacity was limited at the time, and Beijing's influence had already covered North China. On February 11, 1958, Tianjin was changed to a municipality under the jurisdiction of Hebei Province, and the provincial capital was moved from Baoding to Tianjin. However, Tianjin is also an important seaport in the north. Its geographical location is very important, its strategic significance is very prominent, and its population status and urban development scale are among the best in the country. Therefore, it was restored to a municipality directly under the Central Government in January 1967.