Delhi today recorded the coldest morning of this season with temperature dipping to 3.9 degrees celsius. Road, rail and air traffic were affected also due to dense fog.
Twenty-three Delhi-bound trains were delayed by one to six hours due to weather-related conditions in Delhi and different states, according to railways.
According India Meteorological Department (IMD) Indira Gandhi International Airport reported zero visibility due to "very dense fog conditions". The adverse conditions, however, did not have any major impact on flight operations.
Delhi airport authorities however issued an advisory urging passengers to contact their concerned airline for flight information before leaving for the airport.
"Low Visibility Procedures are in progress at Delhi Airport. All flight operations are presently normal. Passengers are requested to contact the airline concerned for updated flight information," authorities said.
The CAT III or Category III -- an instrument landing system (ILS) that allows aircraft to land in low visibility conditions, operations for takeoffs and landings are necessitated when very dense fog causes poor or zero visibility.
"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," they added.
The Delhi-NCR got some relief on Thursday as the sun shone through the thinned layer of fog, but chilly winds kept the temperatures down.
"Cold day" to "severe cold day" conditions have been prevailing over many parts of north India since December 30-31.
A "cold day" is when the minimum temperature is less than or equal to 10 degrees Celsius and the maximum temperature is at least 4.5 notches below normal.
A "severe cold day" is when the maximum temperature is at least 6.5 notches below normal.
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