This paper aims to address lack of uniform method to assess the maturity level of organizations on Sustainability and sustainable business practices required by local and global policies and/or law to steer the enterprise and countries toward achieving NetZero targets and limit global warming. Since COP21-Paris convention, enterprises, especially large and medium scale, are setting their NetZero target. Enterprises need to establish a baseline of their current sustainability level in order to determine science-based target and initiative to be able to achieve their goals. This demands a uniform method of assessing the maturity level irrespective of the size of the organization, the industry or the place of operations. Without this uniformity, comparison and consolidation of sustainability across sectors or countries or global comparison can be misleading due to different methods and practices employed by different companies. This paper proposes a comprehensive approach to assess maturity level of organizations across all the functions and business lines in order to establish a baseline that will provide a starting point for an organization to achieve their NetZero targets. The study combines a multi-disciplinary approach combining all functions including operations, logistics, supply chain, finance, HR, and technology and explains how to deliver the assessment in a structured way to achieve the intended objectives.