ESG investing has quickly established itself as a mainstream strategy in international financial markets as opposed to a niche strategy. Its validity is increasingly being questioned following the intensive use of corporate self-disclosures, uneven reporting guidelines and a lack of demonstration of practical implementation. This paper critically analyses ESG investing by assessing whether ESG measures truly reflect sustainable and socially responsible results or are a mere corporate story. The study determines the gap between reported ESG scores and actual environmental and social impact with the help of quantitative analytical framework. Analysis of primary quantitative data from ESG and investment professionals is performed to determine gaps, biases and inconsistency in rating. Results indicate major discrepancies between the reported ESG performance and the actual impact which indicate the existence of symbolic compliance and selective disclosure. The paper claims that the existing ESG models do not adequately address long-term sustainability metrics and omit the externalities on stakeholders and ecosystems. Through the suggestion of the impact-based evaluation methodology incorporating outcome-based measurement and third-party verification, this study will help enhance the credibility of ESG assessment. The article has implication for investors, regulators and policymakers to enhance the level of ESG transparency, accountability and capital allocation efficiency in sustainable finance.