Large civil infrastructure projects, such as airports, highways, railways, townships, and other developments, are critical for contributing to the social, economic, and environmental pillars of sustainability along with the UN-SDGs. However, it is not enough to simply assess their impacts; organizations and stakeholders involved in creating, operating, and maintaining these projects must also report on them. Recent reports by UNEP indicate that the civil infrastructure sector is slow in adopting these principles of sustainability assessment and reporting. The aim of this study is to develop an integrated approach for assessing the sustainability of civil infrastructure projects and sustainability reporting for organizations and stakeholders while achieving the UN-SDGs. To achieve this aim, the study employs a two-step process. In the first step, a correspondence matrix is derived from the sustainability assessment parameters of various infrastructure rating tools (InRTs), Global Reporting Initiative (GRI) standards, and UN-SDGs targets. In the second step, a composite indicator called the Sustainability Alignment Index (SAI) is developed. The SAI comprises two sub-indices, namely the TBL-Sustainability Coverage Index (TSCI) and the TBL-Sustainability Disclosure Quality Index (TSDQI). The correspondence matrix, indices, and sub-indices are then used to evaluate the quantitative and qualitative aspects of the sustainability disclosures of selected civil infrastructure companies in Asia and Europe. The study's findings question the comprehensiveness of the evaluating criteria used in InRTs. It also reveals the lack of alignment between an infrastructure project's sustainability assessment criteria, GRI standards, and UN-SDGs targets. Moreover, the results emphasize the insufficient coverage of environmental sustainability assessment and reporting parameters in the disclosures made by the companies. The developed correspondence matrix, indices, and sub-indices can be used by organizations for comparing both quantitative and qualitative measures to understand their relative positions. Additionally, it will enable the public, policymakers, and other key stakeholders to compare different dimensions of sustainability more effectively.