Clearer policy from the Biden administration is needed to spur investment in green jet fuel and help bring down emissions for the aviation sector, according to Exxon Mobil Corp.

The White House wants to increase output of so-called sustainable aviation fuel, or SAF, but earlier in March missed a self-imposed deadline on guidelines on how crop-based forms of the fuel would qualify for tax credits. The administration has delayed setting rules as it tries to balance conflicting views from environmentalists and farmers during an election year.