From October 15 to 17, 2019 Hunan (Changsha) Assembly Building and Engineering Technology Expo (hereinafter referred to as "the Expo") was held in Changsha International Convention and Exhibition Center, Hunan Province. At the meeting, the star rating results of Hunan provincial green cities were released. Changsha and Chenzhou were rated as four-star green cities, while Xiangtan, Zhuzhou, Changde, Zhangjiajie and Yueyang were rated as three-star green cities.

Building a green city is to study and discuss the green problems in urban development and the coordinated development mode of city and environment, which is the only way of new urbanization. The significance of measuring the green development index of prefecture level cities in Hunan Province lies in making the abstract complex system of green city understandable and measurable, making the urban management and decision-making departments regularly understand the position of the current city, how the vertical comparison progresses, how far the gap with the real green city is, and how to develop in the future, so as to effectively guide cities to formulate green strategic planning, monitor and evaluate the implementation of the planning, and provide data support and direction guidance for urban planning, construction and development.

During the Expo, Professor Li Jianqi, President of Hunan Two-type Society and City Science Research Association and President of Hunan City College, gave a keynote speech of "green development index and star rating of green city of Hunan Province" at the "green building and architectural acoustics forum" and explained the assessment process in detail. The green development index and green city star rating of Hunan Provincial prefecture level cities are based on the basic data collection of a large number of surveys and statistical yearbooks, and the weight of the index system determined by the analytic hierarchy process and expert scoring method. The experts in the related fields, such as the Political Research Office of the Provincial Party Committee, the Development Research Center of the Provincial Government, the Provincial Academy of Social Sciences, the Provincial Two-type Office, the Provincial Architectural Design Institute, etc., conduct scientific demonstration and finally evaluate the grade.