Calcutta, July 13: Most autorickshaws in Calcutta are running on a fuel that contains at least 50 per cent kerosene or kerosene and naphtha, and causes three times more pollution than petrol, the first known tests of the adulterated oil done on behalf of The Telegraph show.
One sample of the fuel, popularly known as katatel, bought from a roadside shop near Ajanta cinema at Behala and tested by the West Bengal Pollution Control Board, consisted of two-thirds kerosene and a third petrol.
The other, bought from Jadavpur and tested by Jadavpur Universitys automotive engineering department, contains 25 per cent of kerosene and naphtha each, 45 per cent petrol and 5 per cent impurities.
These two are the first known analyses, done by recognised laboratories, of the adulterated oil autorickshaws use in Calcutta and elsewhere in Bengal.
The results largely explain why at least 10,000 people die in the city every year because of pollution, mainly caused by vehicles — and why Calcutta tops the list of lung cancer victims among Indian cities.
AMS (adulterated motor spirit) was a 1:2 mixture of motor spirit (petrol) and kerosene, says the report prepared by Ujjal Kumar Mukhopadhyay, senior PCB scientist.
Such a high proportion of kerosene reduces the fuels combustion efficiency. As a result, a high level of unburnt fuel along with respirable particulate matter (RPM) is emitted by autorickshaws.
RPMs restrict the flow of oxygen to the lungs, which could lead to any number of life-threatening conditions.
It has been scientifically established that an increase of 10 micrograms RPM per cubic metre of air causes a one per cent increase in mortality, Dipak Chakrabarty, the boards chief scientist, had told a meeting at Writers in March.
Already, Calcuttas annual average RPM count is around 45 micrograms above the permissible limit of 60 micrograms. It can only rise with autorickshaws proliferating on the citys streets — as most are illegal no one can tell with certainty how many are there and at what rate they are increasing. Not even perhaps transport minister Subhas Chakraborty, who ought to know and without whose patronage they couldnt have grown to this extent.
The sample tested at Jadavpur University is more harmful because of the presence of naphtha. Prof P.K. Bose, the director of the School of Automotive Engineering at the university, said cancer-causing compounds such as polyaromatic hydrocarbon and benzene are associated with naphtha.
The observation fits in with the PCB finding that the average benzene level in the citys air is on the rise — from 29.15 micrograms per cubic metre during 2004-2005 to 35.58 micrograms in 2006-2007. This is over twice the permissible limit set by the World Health Organisation.
Through fractional distillation, it is found that 1,000 millilitres of the katatel sample contain 450 millilitres of petrol, 250 millilitres of naphtha, 250 millilitres of kerosene and 50 millilitres of impurities which may be highly toxic, according to the analysis done under Bose. He added: Pollution might increase three times or more because of random use of katatel.
An Asian Development Bank study in 2005 said two-stroke three-wheelers — autorickshaws — belch over 98,000 tonnes of pollutants a year, the highest among all transport modes. This study was done on the premise that they were using petrol.
Twisha Lahiry, a scientist who used to work at the Chittaranjan National Cancer Institute and studied the effects of urban pollution on health, quoted from a 2005 report published by the National Cancer Registry under the Indian Council of Medical Research to say that the rate of lung cancer in Calcutta is 18.4 per 100,000 people compared with 11 to 13 in other metropolises.
Lung cancer among women, who mostly dont smoke, is also higher in Calcutta, suggesting the impact of pollution, said Partha Basu, the head of gynaecological oncology at the institute.