NEW DELHI: Observing that air pollution in the national capital was "terrible", Delhi High Court today directed the Centre as well as an amicus curiae to prepare an action plan with suggestions to address the issue.

A bench of justices B D Ahmed and Sanjeev Sachdeva said effects of air pollution in Delhi were clearly visible and no monitoring stations were required to show that it was "terrible".

"Particulate matter, benzene, sulphur dioxide (SO2), nitrogen dioxide (NO2) and carbon monoxide (CO) are the culprits. Now we need to find out why it is happening and the remedial measures that need to be taken," it said.

Justice Ahmed also said that while judges interested in an issue are not supposed to hear it, he was hearing the matter despite being a "victim of air pollution in Delhi".

The bench had taken suo motu cognizance of the issue after taking note of a report that said Delhi was the most polluted city in the world.

Perusing a report filed by amicus curiae Kailash Vasudev, the bench noted that particulate matter (PM) was the highest contributor to bad air quality in the city as it had far exceeded the standard levels of 100 micrograms per cubic meter of air.

In some areas, PM was found to be 400, the court noted and said the levels of the pollutant were "out of control".

The other "culprits", SO2, NO2, CO and benzene, a carcinogen, were products of vehicular and airplane emissions which were found to be high in areas like R K Puram, IGI Airport, Civil Lines, Karol Bagh and other congested areas.

It also asked whether Delhi Pollution Control Committee was concerned over the terrible pollution levels as even the Ridge area showed very bad air quality.

One of the reasons cited by the amicus for increase in air pollution in Delhi was the reduction of forest cover to 15 per cent and fewer notified green areas.