Gurugram/New Delhi, Jan. 14 -- Gurugram on Tuesday saw a slight increase in mercury levels, with the minimum temperature increasing by 2.7 degrees, to 3.2degC, up from its fourth-ever coldest temperature of 0.6degC logged on Monday. Meanwhile, residents of neighbouring Delhi endured a cold wave for the third consecutive day on Tuesday, with the city recording its lowest minimum temperature in at least three years. The mercury plunged to 3 degrees Celsius (degC), the lowest temperature recorded in the city in nearly three years and a stark 4.4 degrees below what is considered normal this time of the year. The India Meteorological Department (IMD) on Tuesday issued a dense to very dense fog warning at isolated places in Gurugram district until Wednesday. On Monday morning, a "yellow" alert was issued by IMD, warning residents to not step out due to a sharp drop in overnight temperatures from 4.1degC on Sunday. The maximum temperature recorded during the day in Gurugram was 20.2degC on Tuesday, according to IMD. District administration officials of Gurugram said that major stretches, including the Golf Course Road, Gurgaon-Delhi Expressway (NH 48) and Sohna Elevated Road had poor visibility due to dense fog in early morning hours. "The lowest visibility reported in Gurugram and nearby areas was 600 metres at 7.30am," a senior IMD official said. In Delhi, the IMD has issued an "orange alert" for cold wave conditions for Wednesday, indicating continued health risks for vulnerable populations. However, a sliver of relief is forecast later this week with the arrival of a "feeble western disturbance" expected to gradually raise nighttime temperatures from Thursday onward, according to IMD's forecast. Meteorological experts point to a shift on the horizon. "The first western disturbance is expected to be mild though, but will still change the wind direction and prevent cold northwesterly winds from blowing across the plains," explained Ashwary Tiwari, an amateur weatherman who runs the account IndiaMetSky on X. Mahesh Palawat, vice president of private forecaster Skymet Weather, said: "The western disturbance will start impacting the mountains from January 15 and bring snowfall there. But its impact over plains will be minimal. What it will do is lead to a change in wind direction to southwesterly, thus reducing the wind chill factor," Meanwhile, winds remained calm until 9am in Gurugram on Tuesday. It picked up to a speed of 12kmph to 17kmph in the north-west direction at 9.30am and continued in a similar trend throughout the day. Officials at IMD confirmed the frost is expected to persist until the mercury levels remain below four degrees. Despite a slight improvement in overall weather conditions, the district's air quality on Monday, according to the Central Pollution Control Board's (CPCB's) daily bulletin at 4pm, the AQI was lodged at 378 in the 'very poor' category. At around 10pm, the district's AQI showed slight improvement at 373, still in the "very poor" category. Among the four active air quality monitoring stations, at 10pm, Sector 51 recorded an AQI of 393; Vikas Sadan lodged an AQI of 427 which is in the "severe" category; NISE Gwal Pahari and Teri Gram recorded AQI at 353 and 318, respectively, according to live monitoring through the Central Pollution Control Board (CPCB)'s Sameer App. Tuesday's minimum of 3degC at the Safdarjung observatory, the primary weather station for Delhi, is the lowest recorded in January since 2.6degC on January 18, 2023. The chill was widespread across monitoring stations: Lodhi Road also recorded 3degC, while Ayanagar registered 3.2degC, Palam 4degC, and the Ridge 4.4degC. For context, the all-time record low for Delhi remains -0.6degC from January 1935, with the lowest in the past decade being 1.1degC on January 1, 2021. IMD classifies a "cold wave" when the minimum temperature dips below 10degC and is at least 4.5degC below normal, or when the actual minimum falls to 4degC or lower - a criteria met at four out of the five manual monitoring stations or observatories in Delhi. "Cold wave conditions persisted, with these likely on Wednesday too. A rise in minimum temperature is likely from Thursday," an IMD official stated. In a striking testament to the severity of the cold, ground frost was reported in isolated pockets of the National Capital Region (NCR). Amateur weatherman Navdeep Dahiya shared images from Gurugram's suburbs showing frost and a handheld monitor reading of -0.9degC. To be sure, the official reading lodged at Gurugram's IMD station stood at 3.3degC on Wednesday. Similar conditions were observed in Delhi's Sainik Farms, where a private weather station recorded a low of 1.1degC. Sahil Pershad, a 42-year-old resident of Sainik Farms, noted the visible impact. "While more frost was observed, particularly on top of cars on Monday, it was much less on Tuesday. Though milder in comparison to Monday, the minimum still fell to 1.1degC," he said. The daytime, however, offered some reprieve from the biting cold, with a maximum temperature of 21.6degC recorded on Tuesday - two degrees above normal. Morning fog was shallow, with visibility dropping to only 600 meters before giving way to bright sunshine after 9am, according to IMD. IMD's forecast outlines a gradual warming trend: minimum temperatures are expected to rise to 4-6degC on Thursday, 5-7degC on Friday, and 8-10degC by Sunday. A series of more western disturbances after January 15 are predicted to halt the mercury's further descent and may bring fresh snowfall to the Himalayan upper reaches....