Developing a Framework for Sustainable Mega Infrastructure Projects Delivery: A Case Study of Niger Delta, Nigeria

Sustainability remains crucial in the construction sector as it plays a major role in a country’s economic growth and development, thus the need for continuous sustainable development (SD) worldwide, especially in poorer nations where environmental degradation and infrastructural deficiencies are still present. The Niger Delta area of Nigeria is a typical example of this problem because of its historical underdevelopment, ecological fragility, and sociopolitical complexity. Global sustainability frameworks like the Building Research Establishment Environmental Assessment Method (BREEAM) and Leadership in Energy and Environmental Design (LEED) provide helpful standards, but because of their high costs, institutional flaws, contextual inapplicability, and disregard for social factors, they are mainly inappropriate for areas like the Niger Delta, though applied in many developed countries The urgent need for a locally flexible sustainability framework suited to the implementation of mega-infrastructure in the Niger Delta is addressed in this paper. Thirty-one stakeholders, working in Nigeria's construction sector, participated in semi-structured interviews using a qualitative methodology. The results show that inadequate regulatory enforcement, dispersed stakeholder participation, and a lack of context-sensitive guidance impede the implementation of sustainability in mega-infrastructure projects. The study also identified important enablers, including the creation of a project selection committee that includes all stakeholders, the incorporation of regional/localised materials and technology, planning resilience, and effective project management. Based on these observations, the paper suggests a multi-phase framework for implementing sustainability that integrates stakeholder-specific deliverables and systems thinking throughout project lifecycles, from inception to decommissioning. The framework places a strong focus on openness, trust, adaptability, and strategic alignment with the objectives of national development. By providing a reproducible framework for developing sustainable mega-infrastructure projects that addresses Nigeria's pecculiar institutional, socioeconomic, and environmental challenges, this study advances knowledge. According to the findings, sustainable building is not only essential for accomplishing the UN 2030 Agenda, but it is also impossible without regional, workable frameworks backed by stakeholder commitment and policy enforcement. By bridging the gap between regional realities and global best practices, this research offers a path for the execution of sustainable mega-infrastructure projects in high-risk areas such as the Niger Delta.