Dense fog blankets Delhi and parts of North India; flights, trains delayed

The national capital continues to be enveloped in thick fog on Wednesday morning, delaying over 35 flights and numerous train services.

The fog reduced visibility at several places in the morning, the India Meteorological Department (IMD) said. On Wednesday morning, the visibility in Delhi was recorded at 50 metres while the Palam observatory near the Indira Gandhi International Airport recorded a visibility level of 125 metres but kept dropping. 

The average air quality dropped to 381, "very poor" on the Air Quality Index and the minimum temperature in Delhi dropped to 7 degrees Celsius.

"As per satellite imagery (0515 hours IST), a layer of dense fog has been established over northwest India and adjoining central India, including Punjab, Haryana-Chandigarh, Delhi, UP, north Raj, north MP," a post by IMD read.

The Delhi airport has issued an advisory that instructed passengers to contact their airlines. "While landing and takeoffs 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 advisory stated.

Trains delayed 

As many as 25 trains headed to Delhi are delayed. The Railways on Tuesday deployed around 19,700 GPS-based navigation devices, known as Fog PASS, to help loco pilots operate trains through the thick fog. This will help with minimal disruptions and delays while ensuring the safety of passengers.

"Every year we increase our procurement so that we have enough stock of the device to use in times of need. In March 2021, we had around 12,742 Fog PASS devices," a senior railway official said. "As the number of trains are increasing with the introduction of new trains, we have increased our procurement of Fog PASS devices as well," he added.

Fog PASS is a hand-held portable device given to loco-pilots for assistance in navigating dense fog conditions. The device gives them on-board real-time information (display as well as voice guidance) regarding the location of fixed landmarks such as signals, level crossing gates (manned & unmanned), permanent speed restrictions, neutral sections etc.

 "It displays approach indications of the next three approaching fixed landmarks in geographical order accompanied with a voice message at 500 mt on approach. Route survey for collecting the GPS/GNSS coordinates of landmarks is required to be carried out separately & programmed," the official said. The device also shows the speed of the locomotive, distance and time to reach landmarks and is carried by the Loco Pilots.