Calcutta is the country’s lung cancer capital, according to the National Cancer Registry. Calcutta is the country’s wheeze and cough capital, say leading pulmonary specialists.

But what is it that makes a resident of the city more susceptible to lung cancer and bronchial distress than his counterpart in other metros?

Doctors blame it on the cocktail of toxic gases that the city’s transport fleet belches out. And the two-stroke auto (often run on adulterated oil, commonly referred to as katatel) accounts for 98,025 tonnes of pollutants every day, says an Asian Development Bank survey.

The good news for Calcutta residents is that the high court has ordered all two-stroke autorickshaws — 37,000 registered ones and almost an equal number of unregistered vehicles — off the city roads by December 31. The bad news is that the government is yet again trying to dodge the deadline.

For every single day that Operation Phaseout is delayed, Calcuttans are at increased risk of contracting a respiratory or cardiac disease. Metro compiles a Q&A on the impact of auto emission on our health.

I don’t commute by autorickshaws. How does the phaseout affect me?

If you breathe the Calcutta air, you are affected. Period. Nobody — you, your parents, siblings, spouse or children — is safe as long as the two-stroke autorickshaw and other polluting vehicles poison the air we breathe.

Autorickshaws contribute 69 and 43 per cent of the hydrocarbon and carbon monoxide, both toxic gases, to the Calcutta air.

“This is only the emission calculated from registered autorickshaws assumed to be plying on petrol. If we take into account the fact that there are almost as many unregistered three-wheelers within greater Calcutta that run on katatel (a cocktail of petrol, kerosene, naphtha and other toxic substances), the level of pollution will be far higher,” says automotive expert Probir Bose.

Where is the health impact of auto pollution first felt?

In the mother’s womb. “Air pollution can cause chronic lung problems for both unborn babies in the mother's womb and for infants,” warns paediatrician Ashok Modi.

What diseases can be triggered by auto emission?

Studies have confirmed that the city has a high incidence of lung cancer, and respiratory, cardiac and kidney distress caused by air pollution. The National Cancer Registry, maintained by Chittaranjan Cancer Hospital, mentions that the rate of lung cancer in Calcutta is 18.4 per 100,000 people, as against 11-13 in the other metros.

Blame it on the suspended particulate matter emitted by polluting vehicles that invade the lungs.

“There has been a manifold rise in the prevalence of chronic cough, bronchitis and asthma, for which polluting vehicles, especially autos, are to blame. An even more alarming trend is the incidence of lung cancers like adenocarcinoma among young non-smokers,” says pulmonary consultant Asok Sengupta.

The incidence of coronary artery disease has increased from 8 to around 14 per cent over the past decade. “The impact of pollution on cardiac condition is more visible in winter, especially among senior citizens and children,” says cardiac surgeon Kunal Sarkar, calling the go-slow against polluting vehicles “a criminal offence”.

What does the environment department say?

“The health problems posed by the polluting autorickshaws are too many to ignore,” says environment secretary M.L. Meena.

What does the environment department say?

“The health problems posed by the polluting autorickshaws are too many to ignore,” says environment secretary M.L. Meena.

What does the transport department say?

“We need more time to tackle a problem of this magnitude,” says minister Subhas Chakraborty.