Has the EU Emissions Trading System been effective?

The EU Emissions trading system is the first and most popular carbon market that allows the trading of evidence that the EU ETS framework has reduced Greenhouse Gas (GHG) emissions using different models. However, have these emissions reduced industry-wide or simply reallocated over time? This paper adapts a different approach from existing papers: a panel regression model of 27 industrial sectors and 4581 firms across 26 countries between 2006-2020. I find that emissions in polluting increase if allowances increase on aggregate, but more for firms which need permit flexibility