New Delhi, Jan 15 : Amid chaos over flight delays and cancellations due to adverse weather conditions, the Directorate General of Civil Aviation (DGCA) on Monday allowed airlines to cancel flights that are likely to be delayed beyond three hours, an official said, adding the aviation watchdog has also issued new Standard Operating Procedures (SOPs). The SOP states: "Facilities to be provided to passengers by airlines due to denied boarding, cancellation of flights, and delays in flights." The SOPs lay down a framework that mandates airlines to adhere to specific measures to alleviate the inconvenience faced by passengers during extended delays, especially in the wake of adverse weather conditions. One of the key provisions of the SOPs is the requirement for airlines to prominently display the reference of the CAR -- civil aviation requirement -- on all flight tickets. This ensures that passengers are made aware of their rights and the procedures to be followed in the event of flight cancellations or delays. Delhi's Indira Gandhi International Airport in the last two days has experienced significant disruptions with nearly 600 flights delayed, and 76 flights cancelled due to dense fog and poor visibility. This has caused a ripple effect across airports in the country. As per sources, the primary reason for the chaos is the limited operational capacity of the airport's runways. The India Meteorological Department on Monday said that dense to very dense fog conditions are likely to continue to prevail across north India during the next three days and dense fog thereafter. /IANS