The air we breathe is a killer.

This fatal fact was finally tabled on Wednesday at a closed-door meeting in Writers’ Buildings, chaired by Subhas Chakraborty.

Alarming Air Quality of Calcutta: A Real Health Concern, was the presentation by Dipak Chakraborty, the chief scientist of the state pollution control board (PCB).

“The cost of inaction will be too high,” he warned.

How high? Linking poor air quality with mortality, the presentation stressed that at least 10,000 people die in Calcutta every year due to foul air, caused primarily by vehicular emission.

“It has been scientifically established that an increase of 10 micrograms per cubic metre of respirable particulate matter (RPM) causes one per cent increase of mortality,” said the chief scientist.

Calcutta’s annual average RPM count is about 45 micrograms per cubic metre above the permissible limit of 60 micrograms, pushing the mortality rate to alarming levels.

With figures showing how the RPM count in Calcutta was highest among all metros apart from Delhi, minister Chakraborty was forced to take a U-turn weeks after he had proclaimed in the Assembly that the city’s air was cleaner than all other metros.

“There is no way out. Now we must take serious action to improve the quality of air,” said Chakraborty, suddenly waking up to the danger that Metro has been highlighting for months.

The minister even went on to state how Coimbatore — the venue of the CPM party congress — has “more vehicular traffic than Calcutta, but far less pollution levels”.

Chakraborty lost no time in making another one of his grand announcements immediately after the meeting. “After Poila Baisakh, all autorickshaws in the city will be converted to LPG,” claimed the minister.

Compulsory conversion of three-wheelers to LPG was one of the key suggestions for emission control in the pollution control board report presented on Wednesday.

What the minister left unsaid was that if there are around 20,000 registered autos in the city, there are over 30,000 unregistered ones which will not come under his promised clean-fuel drive.

“The government has failed to do anything regarding conversion to clean fuels. If the minister does not walk the talk this time, there will be no escape from this gas chamber called Calcutta,” warned environmentalist S.M. Ghosh, who hoped that the presentation to Chakraborty would finally hit home.

The environment department, for once, pulled no punches on Wednesday as it set out to convince the transport minister and the transport operators present that it was a do-or-die battle ahead for the city.

The meeting had been convened to finalise how the environment department’s notification — “no pollution under control (PUC) certificate, no fuel for diesel-driven vehicles” — would be implemented from from June 5.

The presentation focussed on the peril. “You have all seen the condition of the city’s air.... The time for requests is over. We must enforce corrective measures,” said environment secretary M.L. Meena.

According to the report, diesel-driven vehicles are the prime culprits for the polluted air by emitting finer particulate matter and nitrogen oxides.

“What is most dangerous is that about 74 per cent of these particles are so small that they can enter deep into the lungs and cause maximum damage,” said chief scientist Chakraborty.

The report also pointed out how the level of benzene — a pollutant that is a cause of leukaemia — is close to double the permissible limit in the city.

“Benzene is emitted by petrol-driven vehicles and the polluting autos are the worst culprits,” explained an environment department official.

The green brigade admitted that it was going red in the face trying to cover up for the lack of action on the clean-air front.

“Whenever the Opposition says something about the environmental condition in the city, we have to duck, but I have to admit that the city’s air status is really poor,” environment minister Sailen Sarkar said at the Writers’ meeting.