New Delhi, Dec 26 : Delhi's Indira Gandhi International (IGI) Airport faced substantial operational disruptions as a thick blanket of fog enveloped the national capital. The dense fog resulted in diminished visibility, leading to significant delays in the schedules of various flights. In total, 30 flights were impacted by the adverse weather conditions, as per airport officials. "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 on Tuesday. The India Meteorological Department (IMD) said that dense to very dense fog is likely to continue over Northwest and parts of adjoining Central India during the next 3-4 days. In its bulletin, the weather forecast agency said that dense to very dense fog conditions are very likely to continue in early hours/morning hours in some pockets of Punjab, Haryana, Chandigarh, Delhi and Uttar Pradesh during Tuesday-Thursday and over Rajasthan & north Madhya Pradesh on Tuesday and Wednesday. /IANS