The researchers looked at how emissions trading schemes (ETSs) can be influenced and manipulated, focusing on the European Union Emissions Trading Scheme (EU ETS). They analyzed historical data and existing studies to understand why manipulation might have happened in the EU ETS. Their tests showed that the EU ETS carbon markets were not very efficient at first, but they are getting better over time. Manipulation of carbon markets affects the accuracy of carbon prices, which are important for the success of ETS. This study suggests that ETS regulations and designs need to be improved to prevent manipulation and make emissions trading schemes more effective.