When the temperature of the air near the earth decreases from the normal temperature to about five to six degrees Celsius, it is usually called a cold wave.
In India, more than 13 states and union territories north of the Tropic of Cancer are wholly or partially facing the havoc of the cold wave - Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Haryana, Punjab, Uttar Pradesh, and Delhi are more affected.
Not all the people perceive the cold temperatures in the same way.
People should always follow the instructions in regard to cold waves and keep essential supplies like food, medicines, and adequate winter clothes ready in advance.
What to do:
Listen to the radio, watch TV, read local weather forecasts.
Stay indoors as much as possible.
Wear multiple layers of light, warm clothing instead of a layer of heavy clothing.
Eat enough to supply heat to the body and avoid dehydration.