• Accurate forecasts under the Winter Fog Experiment (WiFEX) have provided significant benefits to airlines, including reduction in flight diversions and cancellations, minimising economic losses and passenger inconvenience.

• The WiFEX, launched in the winter of 2015 at the Indira Gandhi International Airport, New Delhi, has now completed 10 years of dedicated research into North India’s dense winter fog and its impact on daily life and aviation safety.

• The government now plans to launch WiFEX-II, which will extend localised, runway-specific fog predictions to more airports in north and northeast India.

What is WiFEX?

• The presence of heavy and extended period fog is one of the major weather hazards, impacting aviation, road transportation, economy and public life. 

• Led by the Indian Institute of Tropical Meteorology (IITM), under the Ministry of Earth Sciences (MoES), with support from the India Meteorological Department (IMD) and the National Centre for Medium Range Weather Forecasting (NCMRWF), WiFEX is one of the world’s few long-term open-field experiments focused solely on fog.

• It was launched in the winter of 2015 at Indira Gandhi International Airport (IGIA), New Delhi.

• The main objective of this project is to study the characteristics and variability of fog events and associated dynamics, thermodynamics and fog microphysics, with the aim to achieve a better understanding of fog life cycle and ultimately improve capability in fog prediction.

• WiFEX has now completed 10 years of dedicated research into north India’s dense winter fog and its impact on daily life and aviation safety.

• It generates high-quality observational data to develop a reliable high-resolution fog prediction model that could help the aviation and transport sectors manage the disruptive impacts of dense fog.

• Based on comprehensive field observations collected over the past 10 years, the IITM has developed an advanced probabilistic high-resolution fog prediction system with an impressive skill rate of above 85 per cent in forecasting fog onset, intensity, dissipation timing, and duration for airports and surrounding regions in north India.

• A prediction model has been developed which can now forecast a fog-related event at least 18 hours in advance and can also predict the fog’s intensity and when it will dissipate.

• The accurate forecasts produced under WiFEX have provided significant operational benefits to airlines, including reductions in flight diversions and cancellations, thereby minimising economic losses and passenger inconvenience.

• What began at the IGIA, India’s busiest and most fog-affected airport, has now grown into a robust observational network reaching the Jewar Airport in Noida and Hisar in Haryana, covering key aviation corridors across north India.

• WiFEX’s contribution goes far beyond forecasts. This pioneering effort has pushed the frontiers of fog science, revealing how air pollution, urban heat islands, land-use changes, and tiny airborne particles influence fog thickness and duration.

• These findings are now improving early warning systems and helping policymakers design better urban and air quality management plans.

• WiFEX-II will extend localised, runway-specific fog predictions to more airports in north India. 

• By installing dedicated sensors at additional sites, airport operators will gain real-time data to help them activate response plans and ensure operations remain safe and efficient — even in the thickest fog.