A blanket of dense fog encompassed the Uttar Pradesh capital Friday, affecting road traffic and railway services.
Many trains to Lucknow were delayed by hours, prominent among these was the Lucknow Mail from New Delhi.
Early morning commuters and school children had a tough time here as the visibility dropped to less than 40 metres.
The Met Office said the dense fog appeared around 3 a.m. Icy winds added to the winter chill, forcing people to remain indoors.
The weatherman attributed the fog in the plains to snowfall in the hills earlier this week.
Officials added that it usually begins to get foggy mid December onwards, but it happened earlier this time.
The maximum temperature Thursday was 24.3 degrees Celsius, slightly below the season's average, while the minimum hovered around 7 degrees Celsius,a degree below the seasons' average.
