At least nine trains were running late on Wednesday as visibility in some parts of northern India plummeted below 200 meters.

The list of the delayed trains included Purushottam Express for Puri, Mahabodhi Express Gaya, Brahmputra Mail, BGP Garib Rath (Bhagalpur to Anand Vihar), Swatantra S Express (Jaynagar-Delhi), Poorva Express (Howrah junction to Delhi), Brahmaputra Mail (Dibrugarh to Delhi), West Bengal Sampark Kranti Express (Sealdah to Anand Vihar), Kaifiyat Express (Azamgarh to Delhi), Vikramshila Express (Bhagalpur to Anand Vihar).

"The visibility is likely to remain below 200 meters due to dense fog. It may improve to 800m in the shallow fog after some time," said the India Meteorological Department in its daily report.

The air quality in the national capital remains in 'very poor' category which is going to deteriorate slowly, as according to the System of Air Quality and Weather Forecasting And Research. the deficit benefit due to rainfall wash out is levelled off.

Delhi's air quality index (AQI) observed the concentration of Particulate Matter 2.5 under 'very poor' category. However, Particulate Matter 10 shows slight improvement reaching 'moderate' category.

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