Exploring the transatlantic origins of the plot ratio from New York to colonial Hong Kong

Authorship: Junwei Li, Kar Him Mo* (*=corresponding author)

Publication Date: November 2025

Abstract: This study provides the first comprehensive analysis of the historical connection between New York City’s 1961 zoning regulations and the introduction of the plot ratio in Hong Kong’s 1962 Buildings Ordinance. While prior scholarship has noted possible American influence, the specific pathways, timing, and motivations have remained unclear. This study finds that while the terminologies related to plot ratio are inherited from British and American precedents, the calculation formula, bonus mechanism, and maximum permissible number ruled in the Buildings Ordinance are aligned with New York standards. Even so, the motivation behind adopting such a hybridized approach was found to be significantly different after addressing tensions between private property rights, the ambiguous legal basis of administrative zoning, and the preservation of colonial spatial hierarchy. The findings indicate the plot ratio is not a technical innovation within the local ordinance. By tracing the plot ratio’s origins as a key planning instrument, this research deepens our understanding of transcontinental knowledge transfer in colonial contexts and demonstrates how regulatory innovation can emerge through pragmatic adaptation to local political and legal conditions.

Publication Journal: Planning Perspective