Announcing emergency measures for situations when the air is severely polluted, the tribunal chairperson Swatanter Kumar said there was need to define a level at which these measures should come into force.

“Fixing this limit beyond 100 micrograms per cubic metre (the standard for 24 hours) for PM10, for example, is impossible,” Kumar said.

“These measures are for extraordinary conditions… There have been times when the severe category on the National Air Quality Index, which starts at 431 micrograms per cubic metre for PM 10, has been left far behind this season. The concentration reached 1,990 micrograms per cubic metre at one point in Delhi. This is the extent of pollution that residents of Delhi are exposed to.”

“Emergent measures have to be taken to control air pollution once it crosses these limits… when air pollution enters the severe category, then immediate steps are required to be taken as environmental emergency. If…the values (of PM10 and PM2.5) reach 500 and 300 respectively, it is a case of emergency. All usual norms to stop pollution are to be followed at this time in addition to emergency measures,” he said.

The emergency measures include sprinkling water from helicopters, stopping construction activity and halting work of stone crushers.

The tribunal also asked all states to start moving to vacuum cleaning of roads.

“Gradually, cleaning of dust from roads manually should be stopped and mechanical cleaning should be introduced. Manual cleaning only helps in regeneration of pollution,” Kumar said.

The tribunal also identified the sources of pollution based on the various studies presented to it over the course of 21 months.

Coming down heavily on Delhi, Punjab, Haryana, Rajasthan and Uttar Pradesh, the tribunal chairperson Swatanter Kumar said the state governments had only shifted blame on to one another and not done anything to fight pollution.

Kumar said Punjab government’s claim that concentration of PM 2.5 was below the standard limit of 60 micrograms per cubic metre was “impossible”.

Punjab’s monitoring stations are only located in Amritsar, Ludhiana and Jalandhar. Districts with majority of land under cultivation do not have monitoring stations.

“It is most important that the situation Delhi faced in the last 10 days should not happen again,” Kumar said.

DMRC to reply to NGT

The tribunal, in a separate case asked the Delhi Metro Rail Corporation (DMRC), to inform it about the steps it was taking to check air pollution in Kaushambi. “DMRC shall file an affidavit on what appropriate steps they are taking to ensure that it does not generate air pollution from its yard in the Sahibabad Industrial area. It is stated to be located quite close to Kaushambi,” the bench said.