Shimla / Varanasi, Dec 29 (ANI): Cold wave and dense fog tightened its grip over North India on Sunday disrupting normal life with plummeting temperatures and low visibility, forcing people to stay indoors. Although people opine that this year the intensity is not as much as it was in 2012, the mercury is slowly dipping. A migrant labourer said that in spite of having multiple layers of clothing and turning to traditional methods of keeping warm, nothing was working out to fight the chill. Biting cold has taken a toll on health of children and elderly. Temperature is plummeted due to snowfall in the upper reaches, which has impacted northern states such as Punjab, Haryana, Delhi and Uttar Pradesh.