Eight Chinese and two Indian airlines face fines of up to several million euros for not paying for their greenhouse gas emissions during flights within the bloc, the European Commission said on Friday.

It said member states could fine the firms, among them Chinese flag carrier Air China, under the terms of the EU's Emissions Trading System which is designed to cut the carbon dioxide pollution blamed for global warming.

In a highly controversial move last year, the EU added airlines to the ETS regime, sparking howls of protest from the United States and China which said the move breached international law.

Beijing even went so far as to threaten retaliation against the EU, its biggest single export market, adding to a growing list of trade disputes souring ties.

As the protests mounted, Brussels backed off and suspended the ETS for non-EU airlines flying to and from the bloc, with the aim of negotiating a solution by a September meeting of the International Civil Aviation Organization.

On Friday, it made clear, however, that non-EU airlines were still liable to pay for pollution on flights made within the EU.

For example, a Chinese airline may land in Athens first and then fly on to Munich to pick up passengers before returning to the home destination.

It said that almost all airlines had fully complied with their ETS obligations, which were consistent with international law and conventions.

However, eight Chinese carriers, including majors such as China Airlines, China Eastern and China Southern, alongside Air India and Jet Airways (India) were at fault, it said.

The eight Chinese companies were liable to fines of some 2.4 million euros combined while the two Indian groups owed much less, at 30,000 euros.