New Delhi, Dec 21 : The Airport Authority of India (AAI) has issued an advisory warning of delays and changes in the flight operations due to reduced visibility, as dense fog gripped North India on Sunday morning.

The India Meteorological Department (IMD) warned of dense to very dense fog, further reducing visibility and compounding the impact of pollution.

Orange alerts, the second-highest warning level, were issued for large parts of Delhi, Uttar Pradesh, Haryana, and Chandigarh, cautioning residents and authorities about possible disruptions to road, rail, and air traffic.

Taking to X, the AAI said, "Fog conditions in parts of Northern India are affecting visibility and may lead to delays or changes in flight operations at select airports. Passengers are advised to check flight updates with their airlines through official channels and allow extra time for airport travel and formalities."

"The Airports Authority of India has deployed passenger assistance teams at affected airports to provide on-ground support. Passenger safety and convenience remain our highest priority," it added.

IndiGo also issued an advisory regarding the impacted flight schedules due to low visibility.

"Low visibility and fog over Bangalore and Amritsar has impacted flight schedules. We're keeping a close watch on the weather and doing our best to get you where you need to be, safely and smoothly," the airline said in a statement.

"We request that you stay updated on your flight status. Please be assured that our teams are here to assist you at every step and provide full support," it added.

Additionally, air pollution levels in the national capital deteriorated sharply on Sunday, edging dangerously close to the "severe" category as dense smog, plunging temperatures, and thick fog blanketed large swathes of northern India.

The deteriorating air quality coincided with challenging weather conditions.

/IANS