UN environment chief Erik Solheim resigned on Tuesday after an audit questioning his huge travel expenses triggered an outcry, UN officials said. The former environment minister of Norway had been at the helm of the Nairobi-based UN Environment Programme (UNEP) since June 2016. A UN audit found that Solheim had spent nearly $500,000 on travel and that he claimed unjustified expenses at a time when the world body is struggling with shrinking budgets.