This story began with an early-morning phone call. "Do you know,' the caller said, "Toyota, TELCO and General Motors are ganging up to start a pro-diesel campaign? They plan to take journalists on freebies to see excellent diesel technology across the world.' Intrigued, I asked if the caller knew anyone who is behind this. He said, "Try Kuldip Sahdev. He works with Toyota.'

If something is underhand, the simplest way to deal with it is to make it open. So I asked the Centre for Science and Environment's Our Right to Clean Air Campaign Team to interview Sahdev, a former Indian Ambassador to Japan. Sahdev came to see us, talked openly, and assured us that there was no such joint effort, though it was true that Toyota is planning to take Indian journalists to Japan to show them its excellent production facilities around the time it launches its vehicles in India later in the year. But in no way is it a pro-diesel campaign, he said. It is just to publicise the work of Toyota. Sahdev sounded convincing.

But in all this a thought came to me: Why are all the major foreign car manufacturers out to sell diesel cars in India and especially in Delhi where we are literally choking on particulate pollution? Don't they know about the dangers diesel emissions pose to public health? Doesn't Toyota know that Japanese scientists have found extremely carcinogenic substances in diesel exhaust? Don't Ford and General Motors know that California is taking strict action against diesel vehicles? Isn't Mercedes-Benz aware of all this?

Indian car companies can possibly make a case that they made investments in diesel technology because they were not fully cognisant of the health threats posed by it. It is a fact that literally no car company has any environmental health specialist on its staff to give it proper advice. But, surely, the foreign car majors know this. Mistakes being made in ignorance is one thing but mistakes being made in full knowledge of facts is totally unforgivable.

So we decided to confront the foreign car companies with a common questionnaire and insisted that we get interviews or written replies from nobody less than the chief executive officers ( ceo s) of these companies. Except for Fiat and General Motors, all others responded. Here is our report....

---Anil Agarwal

Diesel: an urban nightmare
• One person dies prematurely every hour in Delhi due to the extremely high levels of suspended particulate matter ( spm ) in the city's ambient air, according to a study conducted by the New Delhi-based Centre for Science and Environment ( cse ). Moreover, 52,000 people die every year in 36 Indian cities due to high levels of spm .

• The real killers are fine particles