Delhi woke up to cold wave conditions on Friday as the minimum temperature dipped to 3.8 degrees Celsius, according to the India Meteorological Department (IMD).
The city was swept by a cold wave on Thursday as well as the temperature dropped sharply to 3.4 degrees Celsius from 8.4 degrees Celsius on Wednesday.
Similar conditions are likely to persist for the next few days, the weather department has forecast.
The maximum temperature is likely to settle at around 19 degrees Celsius and there will be shallow fog, it said.
The weather stations at Delhi's Palam and Lodhi Road recorded a minimum temperature of 7 degrees Celsius and 4 degrees Celsius respectively on Friday.
In the plains, the IMD declares a cold wave if the minimum temperature dips to 4 degrees Celsius. A cold wave is also declared when the maximum temperature is 10 degrees Celsius and is 4.5 notches below normal.
Delhi had experienced cold wave conditions on December 20 and December 21 as well, when the minimum temperature settled at 3.2 degrees Celsius, the lowest so far this season, and 4 degrees Celsius respectively.
The IMD has forecast cold wave to severe cold wave conditions in northwest India till January 3.
A "severe" cold wave is when the minimum temperature dips to 2 degrees Celsius or the departure from normal is more than 6.4 degrees Celsius.
The city's air quality was in the "very poor" category as the Ministry of Earth Sciences' SAFAR system recorded an Air Quality Index (AQI) of 308 on Friday.
An AQI between zero and 50 is considered "good", 51 and 100 "satisfactory", 101 and 200 "moderate, 201 and 300 "poor", 301 and 400 "very poor", and 401 and 500 "severe".