Setting a new low for temperature this winter, mercury in the national capital Sunday fell to 1.9 degrees Celsius -- five notches below average.
This is the lowest recorded in Delhi in five years. It was in January 2008 that the temperature touched 1.9 degrees, the India Meteorological Department said.
The national capital, with the rest of north India, has witnessed a harsh winter, affecting normal life.
Schools in the city have been ordered shut until Jan 12.
Thirteen trains were cancelled and nearly 60 trains got delayed between two and 12 hours, the northern railway said. Some 25 trains were rescheduled.
But there was no major effect on air traffic, the Delhi International Airport Ltd said.
"It is bone chilling. It is one of the harshest winters I have seen," said Archana, a 40-year-old government employee.
For those spending night in the open, it was hell.
"We gather every bit of wood, paper, plastic, whatever we get, so that we can light a bonfire," said Sukhram, who lives on a pavement in south Delhi. "God continues to be so harsh on us."
Many homeless made a beeline for night shelters as icy winds kept temperatures below average for the past few days.
According to the Delhi government, the capital has 150 night shelters with a capacity to shelter about 10,000 people.
Fog enveloped the city in the morning with visibility dropping to 400 meters at 8.30 a.m. But it cleared in less than two hours.
Saturday's maximum temperature was eight notches below average at 12.6 degrees Celsius, while the minimum was 2.9 degrees Celsius -- four notches below average.