As many as six flights, scheduled to depart from Delhi's Indira Gandhi International Airport (IGI), were delayed due to dense fog, informed airport authority. Among the flight routes affected by the severe fog were Delhi-San Francisco/Kathmandu, Delhi-Chandigarh-Kullu, Delhi-Jaipur, Delhi-Dharamshala-Chandigarh, Delhi-Shimla- Dharamshala, Delhi-Dehradun.