Emissions, Swiss makes its Green Fare mandatory on all domestic flights
It is the first route in Europe on which the ticket price compulsorily includes the contribution for compensation of the [...]

It is the first route in Europe on which the ticket price compulsorily includes the carbon offset contribution. This is the Zurich-Geneva (and vice versa, of course) operated by Swiss.
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The Swiss airline has introduced what it calls 'Green Fares' on its European network since the beginning of the year. The ticket purchased at these fares already includes the environmental contribution. But it is an option in the sense that the passenger can choose (lower, evidently) fares that do not include that contribution.
Starting Sept. 7, however, all fares on Swiss's domestic network automatically include that contribution. Now, since Bern and Lugano are no longer part of Swiss's network, the change applies only to the route between Zurich and Geneva, a route on which the company flies five daily frequencies using an A330-300 and four A220-300s, at fares starting at 104 Swiss francs (109 euros) for one-way and 160 Swiss francs (167 euros) for round-trip (in Economy Light, i.e., with carry-on baggage only).
When choosing the Economy fare (Light, Classic, or Flex), the following inscription appears, "Fly more sustainably thanks to SAF (20%) and offsets (80%)." Meaning that 20 percent of what is paid to offset CO2 emissions will go into the purchase of sustainable fuel and 80% into the development of environmental protection projects. In the case of a flight with from Zurich with a stopover in Geneva or vice versa, the Green Fare applies on a mandatory basis only to the domestic route, not the international route.
"We have a great responsibility to society and the environment," the Swiss company's CEO Dieter Vranckx explained in a note. "We intend to make Swiss entirely carbon neutral by 2025, and to achieve this ambitious goal we need to act in several directions. Adopting only Green Fares on our domestic flights is an important step in this strategy."