Delta adds $3 surcharge to flights to and from Europe - USATODAY.com

Rick Seaney, chief executive officer of FareCompare.com, which tracks fare changes, said "this small change is pretty clearly related to ETS."

Chinese Airlines Won't Pay EU Carbon Tax

China’s airlines will refuse to pay any carbon costs under the European Union’s Emissions Trading Scheme (ETS), while other Asia Pacific carriers, already battling a weak travel market, are likely to pass on the extra cost to passengers.

China, India Mount Opposition Against EU Aviation Carbon Curbs - Bloomberg

The European Union faced increased
pressure to scale down its plan to impose carbon curbs on
airlines after China’s carriers said they won’t comply with the
rules and India signaled it may attempt to scupper the EU plan.

India readies a four-pronged poke to ETS tax on aviation - CNBC-TV18

India is reportedly going to team up with US, Canada, Japan and many other countries to challenge ETS. The first strategy will be to challenge it at the WTO because India believes that ETS is a violation of the National Treatment Norms set up by the WTO. This stems from the fact that the tax charged is not only on the airlines that uses the EU airspace, but also on the route taken to reach the EU airspace.