Cold wave, a relatively new weather phenomenon for Nepal, has swept across the Terai belt of the country, claiming the lives of at least three persons as of Friday, according to Saturday\'s Republica daily. A 21-year-old college student from Govindapur village of Siraha district, reportedly died of hypothermia resulting from extreme cold in Rajbiraj Thursday night. Two more persons had already died of extreme cold the previous night. Weather experts said it had been almost one week since cold wave started engulfing the Terai plains in southern Nepal. \"Cold wave will not recede soon,\" Rajendra Shrestha, a senior meteorologist, was quoted by the daily as saying. \"It is here to stay all through this winter -- albeit only in some parts of the Terai occasionally.\" What is being referred to as cold wave by the general people, and of course the media, is actually a stagnant blanket of thick smog -- a mixture of smoke and fog -- covering the plains of Nepal, Bangladesh and north India. The blanket of smog is a result of industrial and agricultural pollution, said weather experts. \"Until two decades ago, the smog would not stay for so long in the Terai,\" said Shrestha, who has been working at the Meteorological Forecasting Division for the last 25 years now. \"It is because there were not as many industries as they are now in this area.\"