The global shipping industry faces mounting pressure to adopt cleaner fuel options to curb carbon and sulphur dioxide emissions, aligning with broader environmental goals. However, the proliferation of tankers transporting sanctioned oil from Iran, Venezuela, and Russia presents a significant challenge. These vessels, known as the ?shadow fleet?, often evade regulatory scrutiny due to opaque ownership structures and non-Western insurance arrangements, hindering efforts to enforce cleaner shipping standards. The ?shadow fleet? employs various deceptive practices, such as ship-to-ship transfers in international waters, falsifying identification numbers, and providing false location data. This clandestine activity has led to a rapid expansion of the shadow fleet, comprising approximately 14.5% of the global tanker fleet, according to Lloyd's List Intelligence. The surge in shadow fleet activity, spurred by geopolitical events like Russia's invasion of Ukraine and Western sanctions, raises concerns about environmental impact, safety, and the effectiveness of sanctions. Despite regulations like the IMO 2020 convention mandating low sulphur fuel usage, enforcement remains a challenge. Shadow fleet tankers often bypass these regulations by using higher sulphur diesel, which is cheaper and readily available in ports servicing Russia and Iran. While the extent of non-compliance with IMO 2020 regulations is difficult to ascertain, there has been an increase in detentions related to sulphur-related breaches. Port authorities have detained several ships in connection with sulphur emissions violations, with many having previous calls to Russia. Russia and its Eurasian Economic Union partners have agreed to continue using high sulphur fuel until 2026, enabling ships to obtain this fuel at ports servicing these countries. Similarly, Iran continues to supply high sulphur fuel, with recent operations observed in the Middle East Gulf. Efforts to address these challenges include increased inspections of shadow fleet vessels and stricter fines for irregularities. Ship insurers and certifiers are also scrutinizing vessels engaged in suspicious activities to ensure compliance with sanctions and environmental regulations. Despite these efforts, the persistent use of dirty fuel by the shadow fleet underscores the complex interplay between geopolitical dynamics, regulatory enforcement, and environmental sustainability in the global shipping industry. (ET Infra)