Isaac Valero Ladron, the European Commission's spokesman on climate matters, said the EU executive "remains confident that Chinese airlines will comply with EU legislation when operating through EU airports."

The Chinese government said on Monday (6 February) it had barred the country's airlines from joining the EU scheme, which slaps a charge for carbon emissions on all flights into and out of Europe.

But the European Commission, which polices the EU scheme, warned that financial penalties would apply to airlines that refuse to comply with it. According to EU sources, the scheme would add less than €2 to the price of a flight from Shanghai to Europe.

"It would be much more costly for any airline not to comply with the legislation than doing so," Ladron told a press briefing. Airlines that fail to comply will be slapped a fine of €100 for each tonne of CO2 emitted, he said.