European budget carrier Wizz Air has been named the ¡°most emissions-efficient airline¡± according to new rankings released on Wednesday (2 July) by aviation analytics firm Cirium.

The Hungary-based low-cost airline emits 53.9 grams of CO2 per Available Seat Kilometre (ASK), according to Cirium¡¯s calculations, making it the airline with the lowest emissions intensity in 2024, followed by US-based budget carrier Frontier Airlines (54.4 grams) and Turkey-based Pegasus (57.1 grams).

Volaris and IndiGo rounded out the top five, while Jetstar, Spirit Airlines, Scoot, SunExpress and Air India Express also ranked among the top 10 (see top 20 rankings below).

Cirium¡¯s Flight Emissions Review uses the company¡¯s own Emerald Sky methodology to measure CO2 emissions and fuel burn of the world's 100 largest airlines by capacity.

In Western Europe, the 10 most emissions efficient carriers included Wizz Air, Azores Airlines, Aegean Airlines, Transavia and Ryanair, followed by Buzz, TAP Air Portugal, Norwegian, Finnair and SAS.

The report also ranked the CO2 emissions of the 10 largest airlines in the world by ASK, with Ryanair taking the top spot, followed by Southwest Airlines, Delta Air Lines. American and United were ranked fourth and fifth, respectively, followed by Turkish Airlines, China Southern, Qatar Airlines, Air China and Emirates.

Additionally, the report found average passenger CO2 emissions per ASK had?declined 6 per cent globally from 2019 to 2024, largely due to the use of newer, more fuel efficient aircraft.