<br/>Flight operations at the IGI airport in New Delhi remained suspended Tuesday morning due to dense fog which has disrupted the schedule of over 50 domestic and international flights. No flight has taken-off or landed after 8 am as the runway visibility dropped to 50 metres. Sources said, about 12 incoming and outgoing morning flights have been cancelled.<br/><br/>No flight could land even using the CAT-III B instrument landing system, as the minimum permissible limit to land under such conditions is 50 metres, while the limit for low visibility take-off is 150 metres.<br/><br/>AIR correspondent reports that Delhi's airspace would also remain closed for an hour between 11.15 am and 12.15 pm for fly-past of Indian Air Force aircraft during the Republic Day parade. <br/><br/>After remaining disrupted for almost a week, Delhi airport yesterday witnessed a fog-free day helping the airlines to maintain their schedule.<br/>