New Delhi, Jan 24 (UNI) Cold and foggy weather engulfed the National Capital on Sunday, delaying a total of 18 trains due to low visibility conditions and other operational reasons.

The Indian Meteorological Department (IMD) predicted dense to moderate fog in Delhi for the next four days.

The minimum temperature rested at nine degrees Celsius and maximum at 15.

Meanwhile, Delhi's overall air quality stands in the 'very poor' category, according to the System of Air Quality & Weather Forecasting & Research (SAFAR).

The city's minimum temperature rose due to easterly winds and a cloud cover over the city, an IMD official said.

A cold wave occurs in the plains when the minimum temperature is 10 deg C or below and/or is 4.5 notches less than the season’s normal for two consecutive days. A cold wave is also declared when the minimum temperature is less than 4 deg C in the plains.

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