China is gradually and steadily shifting towards more sustainable development and the local governments are increasingly promoting sustainable spatial planning practices. The article debates the potential contradiction between the goal of a growing urban population and the reduced consumption of land planned by the sustainable development strategy of the city of Suzhou in the Yangtse River Delta region. The article explores the opportunities of densification of the residential urban environment as a possible solution for this contradiction. The article presents some Chinese examples of densification for land use efficiency and identifies in the resettlement communities of Suzhou some of the sites that can be efficiently redeveloped for their obsolescent conditions that do not correspond to the increasingly middle-class status of the residents in the region. The article investigates the different options of densification possible in the resettlement communities in the frame of the policies of urban renewal promoted in China in recent years for improving the urban quality of cities.

Currently, historical areas in China are facing issues of color authenticity and excessive commercialization. Colors, as an important element of historical areas, reflect their history and culture. However, there are some flaws in the existing research methods, so a more scientific and systematic method is needed to obtain accurate and objective color visualization results to promote the sustainable development of historical areas. In order to explore the methods and applications of visualizing the environmental color genes of historical areas, Shiquan Street in Suzhou, China was taken as the research object, ArcGIS 10.5 was used to obtain the street veiw photo samples, Matlab was used to summarize the architectural colors of the historical areas, and K-means clustering was used to generate the central color card of the historical areas, thus completing the color visualization of the historical areas, followed by further searching for the color patterns and central colors, so as to explore the strategies for sustainable development of historical areas. The various quantified color models of historical areas can explore the regional uniqueness and color locality of historical areas, which avoids problems such as homogenization of block colors, unclear styles and features, and excessive proportion of commercial colors caused by poor color guidance and control in the design related to historical areas, providing approaches to the research on the harmonious unity of environmental colors and features related to historical areas.