New Delhi, Jan 10 : The national capital woke up to a minimum temperature of 7.1 degrees Celsius, which is the seasonal average, according to India Meteorological Department (IMD), adding that the maximum temperature is likely to hover around 16 degrees making Wednesday a cold day. On Tuesday the city recorded a maximum temperature of 13.4 degree Celsius, six notches below the seasonal average. The city, on Wednesday morning, recorded lowest visibility of 700 m at Safdarjung at 7:30 a.m. while the Palam recorded 800 m at 8:30 a.m. The IMD classifies fog intensity into four types: shallow, moderate, dense and very dense fog. The visibility ranges from 999 m to 500 m, 499 m to 200 m, 199 m to 50 m and less than 50 m, respectively. According to Indian Railways, a total of 18 trains were running late by hours due to fog and cold wave. The Air quality continued to remain in the 'very poor' category at several stations across the city. At the Anand Vihar area, PM2.5 levels remained into the 'very poor' category standing at 307 and PM10 reached 181 or 'moderate'. The CO was at 135 or 'moderate', according to the Central Pollution Control Board (CPCB). The Air Quality Index (AQI) between zero and 50 is considered 'good'; 51 and 100 'satisfactory'; 101 and 200 'moderate'; 201 and 300 'poor'; 301 and 400 'very poor'; and 401 and 500 'severe'. The Indira Gandhi International (IGI) Airport T3 also witnessed PM2.5 levels at 292, the 'poor' category while the PM10 was at 166, falling under the 'moderate' category, respectively. /IANS