Parts of Delhi are predicted to record a severe heatwave on Wednesday, with the maximum temperature likely to hit the 40-degree mark, India Meteorological Department said. Severe heatwave conditions are likely to persist on Thursday as well. IMD officials said a prolonged dry spell has led to "severe" hot weather conditions in northwest India. "The heatwave spell over northwest, central and west India is likely to continue during the next four to five days." For the plains, a "heatwave" is declared when the maximum temperature is over 40 degrees Celsius, and at least 4.5 notches above normal. A "severe" heatwave is declared if the departure from normal temperature is more than 6.4 notches, according to the IMD.?Parts of Delhi reeled under severe heatwave conditions on Tuesday and eight weather stations in Delhi recorded their maximum temperature above 40 degrees Celsius, with the mercury at Narela, Pitampura and the Sports Complex station crossing the 41-degree mark.?Another spell of heatwave in Delhi is likely from April 3 to April 5.?