Over the next three days, Delhi and its adjoining areas are likely to see a drop in temperature, accompanied by intermittent light rain, cloudy sky and fog, with the air quality expected to deteriorate towards the weekend, the India Meteorological Department (IMD) and the Indian Institute of Tropical Meteorology (IITM) said on Wednesday. The IMD issued a yellow alert for Thursday, warning of moderate fog at many places in the Capital. Shallow to moderate fog is expected during morning over the next six days, except on January 31 and February 1, it added. The sky will remain generally cloudy through the week in Delhi, with a possibility of very light rain accompanied by thunderstorm, lightning and gusty winds (30-40 kmph) on the night of January 31, and one or two spells of light rain on February 1.