EU climate commissioner Connie Hedegaard on Monday called on countries fighting an airlines carbon emissions fee to propose concrete action to fight climate change. \"We know what you don\'t like, but what\'s your constructive proposal for a global agreement on aviation?\" the Commissioner for Climate Action asked the countries in a message posted on her Twitter account. Hedegaard also warned that Brussels would not suspend the rule requiring all airlines to buy pollution permits to fly to Europe, despite stiff opposition led by the United States, China and India. Countries opposing the scheme that entered into force January 1 are meeting in Moscow on Tuesday to draw up retaliation measures against the Emissions Trading Scheme. The China Air Transport Association, which represents the country\'s airlines, has warned that Chinese carriers would not pay the charge. Meanwhile, US and Canadian airlines had filed a complaint against the scheme at the EU\'s top court, although the challenge was thrown out by the court. Under the EU scheme, airlines would have to pay for 15 percent of the polluting rights accorded to them in 2012, the figure then rising to 18 percent between 2013 and 2020. It also calls for fines of 100 euros per tonne of CO2 against companies that refuse to comply, or a flight ban as a last resort.