The European Parliament backed jet fuel rules that set mandatory targets for replacing kerosene with less polluting energy sources, but expanded the definition of what a clean fuel could be, Reuters reported.

The requirements, which if approved would be a world first, were originally proposed by the European Commission last year to reduce the climate impact of the aviation sector, which is believed to be responsible for about 3% of global emissions.

The approved text will require suppliers to blend at least 2% sustainable aviation fuel (SAF) with kerosene from 2025, rising to 85% by 2050, more ambitious than the 63% target by 2050, the originally proposed commission.

Under the Commission's initial proposal, SAF would include biofuels derived from recycled waste and, on a smaller scale, hydrogen-based synthetic fuels or e-fuels made from renewable energy sources.

But the version of the rules approved by the European Parliament expanded the Commission's original definition of SAF by adding recycled carbon fuels derived from waste gas and biofuels derived from animal fats or distillates.

Before the vote, EU Energy Commissioner Kadri Simson urged lawmakers not to expand the definition of SAF and to be careful with overly ambitious targets.