Chandigarh, Dec. 30 -- Visibility dropped to zero for the first time in the city as the entire region was affected by very dense fog on Monday morning. As per the India meteorological department (IMD), dense fog will continue till Tuesday, but is likely to improve from Wednesday onwards as rain is on the cards. Visibility dropped to 0 meters at the Chandigarh airport at 8.30 am. At the same time, visibility was at 40 meters at the Sector 39 IMD station while it fell to 30 meters around 5.30 am. During the day the visibility improved but it again started to fall in the evening. Flight operations at the Chandigarh airport were affected on Monday with nine departures cancelled and 14 flights delayed, including 11 departures and three arrivals, leading to inconvenience for passengers. Dense fog severely impacted rail connectivity, leaving hundreds of passengers stranded as several prominent trains arrived at the Chandigarh railway station with significant delays. IMD Chandigarh director Surender Paul said that this fog has come as an active western disturbance is approaching the city. While there is an orange alert for dense fog in the city on Tuesday as well, rain is likely in the city on Wednesday and Thursday. When it rains during the winter, fog is usually washed away. As per IMD officials, fog will remain unlikely on New Year's Eve if these rain spells begin by December 31 and it is likely to continue on January 1 as well. After the rain, dense fog can be expected owing to all the extra moisture in the air. Maximum temperature fell from 21.7degC on Sunday to 16.7degC on Monday, the lowest it has gone this season. It was 3.1 degrees below normal. Before this, this season's maximum temperature fell to 17.4degC on December 25. At 16.7degC, the city was colder than Shimla where maximum temperature was 18.5degC and Dharamshala at 19degC. As the western disturbance approaches, Paul said that we can expect that day temperature will fall further especially if it rains during the day. Night temperature is likely to rise by 2-3 degrees during this period and drop again after the western disturbance passes the region. Minimum temperature has already started to rise. It rose from 5.6degC on Sunday to 7.2degC on Monday, 0.5 degrees above normal. The night temperature was also colder than Shimla at 8.6degC. In the next three days, maximum temperature will remain between 17degC and 19degC while minimum temperature will remain around 6degC. Meanwhile, the air quality of the city continued to be poor for the fourth consecutive day. As per the Central Pollution Control Board (CPCB) daily Air Quality index (AQI) bulletin, AQI of Chandigarh was 253 on Monday which falls in the poor category. AQI between 201-300 is considered poor and can cause breathing discomfort to most people on prolonged exposure. The AQI of Panchkula wasn't calculated on Monday while the AQI of Delhi was 401 which is in the severe category. Flight operations at Shaheed Bhagat Singh International Airport, Chandigarh, were affected on Monday, with nine departures cancelled and 14 flights delayed, including 11 departures and three arrivals. Airport authorities cancelled nine departing flights scheduled till 11.51 pm. The cancelled services included flights to Hyderabad, Delhi, Jaipur, Patna, Bengaluru, Ahmedabad, Pune and Jaipur, operated mainly by IndiGo. Apart from cancellations, 11 departing flights faced delays during the day. These included flights bound for Abu Dhabi, Dharamshala, Jaipur, Delhi, Mumbai, Bengaluru and Hyderabad. Delays ranged from a few minutes to over an hour, affecting both domestic and international schedules. Dense fog severely impacted rail connectivity leaving hundreds of passengers stranded as several trains arrived at the Chandigarh railway station with significant delays. The Kalka Shatabdi was among the worst affected, reaching Chandigarh with a delay of five hours and seven minutes. Similarly, the Lucknow-Chandigarh Express arrived four hours and 30 minutes behind schedule. Long-distance travel was equally hampered....