New Delhi Dec 31 PTI Delhi shivered under a spell of cold wave while the air quality remained in the very poor category on FridayThe minimum temperature dipped to 38 degrees Celsius in the early hours of Friday The city was swept by a cold wave on Thursday as well and the temperature dropped sharply to 34 degrees Celsius from 84 degrees Celsius on WednesdaySimilar conditions are likely to persist for the next few days the weather department has forecastThe maximum temperature settled at 194 degrees Celsius it saidIn the plains the India Meteorological Department 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 45 notches below normalDelhi had experienced cold wave conditions on December 20 and December 21 as well when the minimum temperature settled at 32 degrees Celsius the lowest so far this season and 4 degrees Celsius respectivelyThe IMD has forecast cold wave to severe cold wave conditions in northwest India till January 3A severe cold wave is when the minimum temperature dips to 2 degrees Celsius or the departure from normal is more than 64 degrees CelsiusThe citys air quality was in the very poor category as the Ministry of Earth Sciences SAFAR system recorded an Air Quality Index AQI of 321 on FridayAn 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 severeThe city is expected to record minimum and maximum temperature of 4 degrees Celsius and 20 degrees Celsius on Saturday respectively PTI MAH MAH ANB ANB