The national capital is expected to experience a cold wave for three days starting Thursday, the India Meteorological Department said on Tuesday. The temperature in New Delhi dipped to 5.1 degrees Celsius on Tuesday, three degrees below normal.

The meteorological department declares a cold wave when the minimum temperature is four degrees below normal for three straight days, The Indian Express reported. The minimum temperature on Wednesday was 5 degrees Celsius, and is expected to dip to 4 degrees on Thursday, Friday and Saturday. The maximum temperature is likely to be recorded at 22 degrees on all three days, which is normal for this time of the year.

Meanwhile, the state-run System of Air Quality and Weather Forecasting and Research said in its daily forecast on Tuesday that air quality in New Delhi, which was in the “very poor” category, is likely to deteriorate further on Wednesday and Thursday, IANS reported. “Feeble western disturbance over the northern part of India, fall in temperature, moisture and moderate fog is likely to increase both gaseous and particulate pollutants for the next two days,” the agency said.

The Air Quality Index in Delhi at 4 pm on Tuesday was 353. Most areas of Delhi recorded an Air Quality Index between 300 and 400 on Wednesday morning. An Air Quality Index between 0 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”.