Mohali/Chandigarh, Jan. 4 -- Poor visibility due to dense fog led to the cancellation of 89 flights at the Shaheed Bhagat Singh International Airport over the last 10 days, official data revealed. On Saturday, as the visibility dropped to 600 metres (moderate) at the airport observatory, two flights were cancelled. Both were scheduled to operate to and from Kangra. With the India Meteorological Department (IMD) issuing an orange alert for dense fog until January 6, more cancellations and delays are likely and airport authorities have advised passengers to check the flight status with the respective airlines before heading to the airport. Orange is the second highest of the four-coloured warning system used by the IMD which asks people to be prepared. As per Met officials, fog is expected to reduce from January 7 but isolated places in the region may see dense fog conditions. Rail services were also disrupted on Saturday, for the 11th consecutive day. Among the affected services, the Amb Andaura-Raipur Haryana Express reached Chandigarh 47 minutes late and was further delayed by 1 hour and 40 minutes at Ambala Cantt. The Mumbai-Amritsar Paschim SF Express was delayed by 26 minutes at Chandigarh, while the Daulatpur Chowk-Ambala Cantt train ran about 30 minutes late. The Una Himachal Express from Indore arrived 1 hour and 2 minutes behind schedule. Shorter-route trains also faced delays, though to a lesser extent. Both morning and evening Kalka Shatabdi services were late by 19-20 minutes. The New Delhi-Amb Andaura Vande Bharat Express was delayed by 23 minutes at Chandigarh, whereas the Chandigarh Vande Bharat arrived on time at 2.45 pm. The Lal Kuan weekly Express was cancelled on Saturday. Meanwhile, Chandigarh's air quality index (AQI) improved for the first time since Christmas, settling at 114, which is classified as 'moderate' by the Central Pollution Control Board (CPCB). Over the last 10 days, it had remained in the 'poor' and 'very poor' category. IMD officials attributed the improvement to the recent rain spell - the city had received 13.7 mm rain on January 1. Meanwhile, the AQI of Panchkula also turned moderate at 145 after remaining in the poor range. IMD Chandigarh director Surender Paul said, "The AQI improvement was on expected lines due to Thursday's rain spell. While we haven't had dense fog yet, it is likely in the coming days due to high humidity levels and low temperatures post the rain. Fog during the day keeps the sun from showing up, which leads to temperature inversion - a condition where a layer of warm air sits above the ground, acting like a lid that traps pollutants (smog, smoke), and moisture - and makes air quality worse." Day temps rise, night drops The temperature also showed a slight variation. The maximum temperature rose from 13degC on Friday to 14.4degC on Saturday, 3.8 degrees below normal. The minimum temperature dropped from 9.5degC on Friday to 9.3degC on Saturday, 2.1 degrees above normal. Over the next three days, the maximum temperature is expected to remain between 14degC and 16degC while the minimum will remain between 6degC and 8degC....