Yemen’s Huthi rebels have dropped a threat to impose a tax on aid, a UN official told AFP Friday, in a significant step towards resolving a crisis that has jeopardised the world’s biggest humanitarian operation. United Nations leaders and aid groups held crunch talks in Brussels on Thursday to address obstruction by the Iran-backed militia that has threatened to sever the lifeline to millions at risk of starvation. “The cancellation of the tax is a positive development for sure,” he said, noting that other issues that still need to be dealt with relate to “access and bureaucratic impediments”.