IMD Issues Orange Alert For Dense Fog in Delhi, Affecting Road, Rail and Flight Operations

New Delhi: India Meteorological Department (IMD) has issued an “orange alert” warning for Delhi on Monday, saying that national capital may witness "dense" to "very dense" fog that could reduce visibility to as low as 200 metres in many parts of city and surrounding areas. low visibility in Delhi-NCR is expected to disrupt ro, rail, and air traffic on November 18. Earlier, a warning of delay in flight operations at Delhi airport was issued by aircraft carrier IndiGo and airport authority.

An IMD official, on Sunday, confirmed, “re are chances of dense to very dense fog in Delhi on Monday, with smog expected later in day.” alert comes as national capital experiences one of its foggiest days of season.

IMD forecast for Monday predicts that fog and smog will affect airports, highways, and railway routes, leing to difficult driving conditions and slower travel times across region.

Impacts on Ro, Rail, Flight Operations

According to Delhi Airport officials, Indira Gandhi International Airport (IGI) is equipped with vanced landing systems, including CAT-3 Instrument Landing System (ILS), which allows flights to land even when visibility is as low as 50 metres. However, system cannot support take-offs if visibility is below 125 metres. In case fog at Delhi airport is dense or very dense, n it could cause significant flight delays.

Earlier, on November 13, Delhi recorded its first “very dense” fog of season, causing more than 550 flight delays, according to flight tracking site Flightrar24. next day, despite slightly improved visibility (400 metres), delays continued, with over 350 flights affected.

fog condition in Delhi appeared to be irregular on Sunday with varied visibility in various parts of city. On Sunday, Palam Airport recorded 500 metres between 8.30 am and 9:00 am, while at Safdarjung Airport visibility dipped to 300 metres at 7.00 am.

visibility remained poor throughout day on Sunday as sun's rays failed to penetrate fog. This resulted in peak of poor visibility at 900 metres at Palam in evening and 800 metres at Safdarjung. Notably, visibility on Saturday was as good as 2,200 metres during day.

dense fog is also expected to cause delays on ros and railways. train services may be impacted due to reduced visibility, while speed limits on ros also be kept under check to ensure ro safety.

How Dense Fog Evaluated

IMD classifies fog based on visibility levels:

• Shallow fog: Visibility between 500-1,000 metres
• Moderate fog: Visibility between 200-500 metres
• Dense fog: Visibility between 50-200 metres
• Very dense fog: Visibility of 50 metres or less

Fog is defined as reduced visibility (below 1,000 metres) with relative humidity above 75%. If humidity is lower than 75%, it is considered smog.

Amidst dense fog conditions, IMD has vised residents of Delhi to take extra precautions while travelling and to stay updated on wear conditions throughout day.