Low-visibility conditions and dense fog returned at the Indira Gandhi International Airport on Tuesday, delaying several early morning flights. Fog started to envelop around 3 am and normal visibility dropped below 50 metres by 6.30 am, while the runway visibility range came down to 150 metres. About 40 early morning flights were delayed, airport officials said. No flights were diverted or cancelled due to fog on Tuesday. Flights during the later part of the day operated as per schedule.LVP was lifted at 8.45 am on Runway 28-10 and at 10.15 am on Runway 29-11 am, the official said.