New Delhi: Delhi woke to a thick blanket of smog for the third consecutive day on Wednesday with pollution levels crossing the hazardous mark in the city and adjoining areas.

As per reports, the severe smog in Delhi-NCR is likely to remain the same for next three days, said meteorological department.

Trains and flights services have been disrupted due to the smog. Reports say that smog hanging over the region for the last 48 hours in a row has disrupted services of at least 11 trains departing from the national capital.

The Indian Medical Association (IMA) has declared a public health emergency in Delhi due to hazardous pollution levels. Experts have warned people to refrain from stepping out in open and avoid outdoor physical activities like cycling and jogging.

National Green Tribunal (NGT) too has called the situation an 'emergency' and has asked people to carry 'N95' masks while stepping out in open.

Particulate Matter (PM) 2.5, less than 2.5 micrometres in diameter, which can be inhaled and become lodged in the lungs and blood cells, soared dangerously in the national capital and adjoining regions.

On Wednesday morning, at 7:45 am, the monitoring stations under the System of Air Quality and Weather Forecasting and Research (SAFAR) showed the city's air as severe: Anand Vihar (686), RK Puram (460), Mandir Marg (768) and Punjabi Bagh (679).

Air Quality of Delhi's Lodhi Road area, prominent pollutants PM 10 and PM 2.5 was recorded in 'severe' category in the wee hours today.

Meanwhile, the central Delhi saw a marginal improvement in the air quality in last 24 hours.

Take a look at PM 2.5 level of these regions on Tuesday and Wednesday:

Anand Vihar: 846 (Tuesday) and 835 (Wednesday)

RK Puram: 505 and 460

Punjabi Bagh: 894 and 679

Dwarka: 468 and 343

See Pic: Sector 120, Noida at 6:30am today

Visuals of #Smog from area around Faridabad's Sarai Metro Station. pic.twitter.com/x4tCoZTmTJ — ANI (@ANI) November 8, 2017

The visibility in some parts of Delhi-NCR dropped to 100 metres.

Meanwhile, all primary schools in Delhi have been directed by the government to stay close on Wednesday. Schools in Ghaziabad will remain closed on both Wednesday and Thursday in the wake of the presence of hazardous pollutants in the air.

On Tuesday, Union Environment, Forest and Climate Change Minister Harsh Vardhan requested all state governments in the National Capital Region to take effective steps for mitigating the levels of air pollution and bring them to acceptable levels.

He said that every possible step required to tackle the situation has been already identified and the need of the hour was to put them into action at ground level, which will yield significant results.