Group 1 - The central government has released a significant policy document titled "Opinions on Promoting High-Quality Urban Development," which outlines 23 specific measures across 9 areas to guide urban development towards modernization by 2030 and 2035 [1][2] - By 2030, the goals include significant progress in building modern urban environments, improving living quality, enhancing green transformation, and increasing governance levels [1][2] - The number of cities in China's "trillion-dollar club" has increased from 3 in 2010 to 27 in 2023, indicating substantial economic growth in urban areas [3] Group 2 - There is a notable shrinkage in smaller cities, with the number of small cities decreasing from 493 to 466 between 2010 and 2020, and their population share dropping from 26% to 23% [4] - The central urban work conference emphasizes optimizing the modern urban system as a key task, addressing the need for better coordination among cities of different sizes [4][5] - The policy document outlines three requirements for optimizing the urban system, including promoting integration of urban clusters, enhancing the competitiveness of mega cities, and improving the capacity of small and medium-sized cities [5] Group 3 - The document stresses the importance of enhancing the competitiveness of mega cities while controlling their scale and relieving non-core functions to foster high-quality development [7][8] - As of February 2023, all 22 mega cities have received approval for their spatial planning, with several cities designated as key innovation centers [7] - The need for differentiated development among cities is highlighted, with mega cities playing a crucial role in driving overall urban development and contributing to national modernization [8][9]