The present research investigates the relevance of ISO 14001 certification in ensuring environmental sustainability and minimizing CO₂ emission in different industries, focusing particularly on SAARC nations, such as agriculture, manufacturing, and food processing industries. In using innovative techniques like Grey Relational Analysis (GRA) and Grey-TOPSIS, the research compares data from 2000 to 2014 to analyze the association between ISO 14001 implementation and renewable energy consumption. The results suggest that ISO 14001 certification, when combined with renewable energy schemes, plays an important role in reducing CO₂ emissions—especially in countries like India under severe environmental challenges. Sectoral challenges continue to exist, though, particularly in agriculture and food processing, owing to imprecise definitions of sustainability and laxly enforced regulations. Big companies are more successful in putting into practice ISO 14001 since they attain better environmental and economic performance than small and medium-sized businesses (SMEs), which experience financial and operational limitations. On a worldwide level, Europe is the leader in the uptake of ISO 14001 because of rigorous regulation and demand for sustainability from consumers, while developing markets are behind, calling for specific policy interventions and campaigns. The research highlights ISO 14001's potential for transformation when integrated with renewable energy and policy contexts, and provides useful lessons for policymakers and industry captains seeking to develop sustainable development practices.