New Delhi, Dec 25 : Delhi grappled with a thick blanket of dense fog on Monday, causing visibility to plummet to zero and leading to significant disruptions in flight operations at the Indira Gandhi International (IGI) Airport. The India Meteorological Department (IMD) issued a report indicating that very dense fog had descended upon the airport early in the morning, with the Runway Visual Range (RVR) on all runways registering between 125 to 175 metres. This compelled the implementation of CAT IIIB operations for both takeoffs and landings. 'Very Dense fog with zero Visibility prevailing at Delhi IGI Airport since 0530 hrs IST today. RVR at all RWYs 125 to 175m and Operations are under CAT IIIB, IMD in a post on X. "While landings and take-offs continue at Delhi Airport, flights that are not CAT III compliant may get affected. Passengers are requested to contact the airline concerned for updated flight information. Any inconvenience caused is deeply regretted," the Delhi International Airport Limited (DIAL) said in an advisory for passengers. In response to the challenging weather conditions, airlines, including SpiceJet, issued warnings to passengers about potential disruptions to departures and arrivals. 'Due to bad weather in Delhi (DEL), all departures/arrivals and their consequential flights may get affected. Passengers are requested to keep a check on their flight status,' SpiceJet said in a tweet on Monday morning. As per sources, several flights were delayed and diverted due to poor visibility. Fog enveloped Delhi on Monday morning and the minimum temperature in the national capital dipped to 7.8 degrees Celsius, seasonal average. According to the weather department, the maximum temperature is likely to hover around 25 degrees with mainly clear sky and shallow to moderate fog. /IANS