Dalhousie: The National Green Tribunal has pulled up the state government for its failure to bring down the city's vehicular pollution level by restricting BS III vehicles and phasing out 15-year-old ones.

The eastern zonal bench of the tribunal has also observed that the government has tabled an unsatisfactory report on the matter.

Bharat Stage or BS norms are the standards for vehicular emission. BS IV are the latest in the series, spelling out the toughest norms so far on exhaust fumes of vehicles, the biggest contributor to air pollution in Calcutta.

The state government had recently submitted a report to the tribunal detailing steps it had taken to control vehicular pollution. After going through it, the bench of Justice S.P. Wangdi and P.C. Mishra said: "We... do not find the report to be satisfactory as the most crucial and foundational requirement pertaining to our directions regarding phase out of vehicles more than 15 years and to permit only BS IV vehicles to ply, has not been complied with except to state that the work is in progress."

The tribunal later directed Alapan Bandyopadhyay, additional chief secretary in charge of the transport department, to appear before it on April 24 with a detailed report containing data on the following:

• The number of vehicles, category-wise, plying in Calcutta, Howrah and their surrounding districts, as well as the rest of the state

• The number of BS III-complaint vehicles, category-wise, plying in Calcutta, Howrah and their surrounding districts

• The number of BS III-compliant vehicles phased out so far

• The number of BS III-compliant vehicles entering Calcutta and its adjoining areas since August 11, 2016.

Vehicular pollution has always been a cause of concern for experts dealing with air pollution, especially in metros across India. In 2016, the tribunal had observed that tail-pipe emission of vehicles and "re-suspension of road dust" had a direct correlation to the amount of particulates in the urban air.

Health experts are unaninous that prolonged exposure to particulates can trigger a host of critical ailments, including lung cancer.

"In the West, the owners of vehicles with old emission norms have to pay a higher tax. We don't have the system here. At least we can stop the plying of such vehicles," said Subhas Dutta, environment activist and the petitioner in the case.

Two years ago, the tribunal had ordered that BS III-compliant vehicles be allowed to enter the city against a fee and on production of the pollution-under-control certificate.

A transport department official said: "The phasing out of 15-year-old vehicles is on. As for BS-III, we have done some work, which we will inform the tribunal."