According to preliminary data, the vast majority of heavy industrialised plants covered by the European Emissions Trading Scheme (ETS) recorded an overall increase in CO2 emissions in the order of 1-1.5 per cent in 2006. The credibility of the ETS relies on creating a scarcity in the market for pollution allowances leading to high carbon prices and greater incentives for companies to cut their emissions. Where there is an over-allocation of pollution allowances carbon prices fall, so the European Commission is assessing all national plans to ensure the necessary scarcity in the European carbon market. Fully verified data for 2006 is not expected until mid May 2007.