Do you want a country full of cars? Cars cause cancer. Scientists can even measure the cancer potency levels of the cars we ride. The so-called cancer potency index has emerged as an important tool for risk assessment the world over. But think twice before you buy a diesel car over a petrol car. Swedish consultants at Ecotraffic found potency levels of diesel exhaust from Indian cars to be more than twice that from petrol. A German government finds diesel cars to be even worse. Meanwhile, more evidence has emerged that diesel emission is not only cancer-causing but can also trigger serious allergies and affect the poor the most. Down To Earth presents the findings of the three studies on the subject