The indispensable significance of megaprojects to a nation’s economy, society, and infrastructure demands ongoing efforts to alleviate the environmental consequences they produce. Nonetheless, the adoption of sustainable practices and legislation is infrequent in developing countries, chiefly due to the substantial expenses linked to sustainable construction methods. The fundamental goal of this quantitative research is to establish a framework for the execution of sustainable practices and regulations. It aims to provide indicators for these rules, examine their relationship with these dimensions, and ultimately explore the moderating influence of cost. Data from the Zambian construction sector were acquired and evaluated using the partial least squares approach. The analysis indicated that the indicators were ideal for implementing rules and sustainable practices to mitigate the environmental impacts of megaprojects, primarily because of their strong correlation with the variables. Secondly, they enhanced the correlation between sustainable construction and the reduction of environmental damage. Third, the adverse impact of elevated expenses in this relationship obstructs the implementation of these policies. The results demonstrate that elevated expenses hinder the execution of certain regulations. A reduced expense for sustainable construction would significantly promote the implementation of these regulations. This study lays out a framework for the construction industry to adopt and follow environmentally friendly rules and practices. These recommendations will lessen the damage that big projects do to the environment and improve the connection between sustainable construction and the environment.