Sadiq Khan has been slammed for “misleading” Londoners with his environmental claims about the expansion of Ulez in its radio advertising. The Advertising Standards Authority (ASA) said claims made by Transport for London (TfL) about pollution levels in the capital were not accurate. It warned the mayor to ensure in the future it has evidence to back up the claims it makes in its marketing. The watchdog looked at six claims made by TfL before Ulez’s expansion in August and found that three were misleading. TfL claimed that levels of nitrogen dioxide had reduced almost by half due to the scheme…