It was quite a good idea in theory. Start with the Harleys, shoehorn in the diesel engines, saw off the back end and weld on an 8 seat people-carrier. Stretch the front forks and lever in a car tyre. It wasn't going to do much in the way of cornering again but you were away. All problems solved and still time for something to eat.

One look at an MCR says it must have been designed by committee but 7 decades later they are still a fixed part of the Delhi scenery, plying their trade along half a dozen fixed routes across a noisy, crowded city, puking great clouds of fumes into the already polluted air. They might get the job done but environmentally friendly they are not.

Technically the MCR is a dream because it is so simple. Most still run on their original 3-speed Harley gearboxes, one of the few things to come out of Milwaukee that was built to last. The 1 litre, 10 horsepower engine fits snugly into the frame and sends sedate power not only down the drive shaft but also to a fairly optional light, occasional ammeter and obligatory horn. In a city with a traffic system like this, a horn is the only tool you need to get through the chaos.

All the fancy bits are long gone. Dials and switches were mostly plundered from the late 70's onwards for the American market and those familiar bulbous petrol tanks are now slowly filling with dust. A cavernous new tank, good for 3 or 4 days' driving was sited under one of the bench seats with a simple gravity feed down to the carburettor.

As for fuel economy the claims are for anything up to 75 km/litre - around 100 mpg. Not bad when you consider that ? will buy nearly 8 litres of the stuff in India. On the other hand, diesel and petrol are almost always diluted with something cheaper; often kerosene, sometimes water, occasionally - well, work it out for yourself. But even without the additives the noxious gases that belch out from its rear end are quite revolting; getting stuck behind an MCR in one of Delhi's frequent traffic snarl-ups is something best avoided. Come nightfall the city descends into a misty gloom, redolent of a dust cloud coinciding with an eclipse.

The ubiquitous mechanic-wallahs will do their roadside workovers wherever something seizes up or falls off and the MCRs get a major overhaul every couple of years, when the engine is stripped down and the tyres re-treaded (allegedly - I didn't see one MCR in Delhi with a trace of tread). The morning pre-ride inspection seems to consist of ambling around the machine kicking the tyres. This serves not only to check for punctures but also confirms that none of the wheels have fallen off.

Shami Joginder Singh has been driving an MCR for 8 of his 22 years, on the same fixed route from Connaught Place at the northern end of New Delhi to the Red Fort, deep in the sprawl of the old city. Eight years of choking pollution and cheap cigarettes haven't done much for his constitution but he was happy to have a job, as was his money lender. "I bought my MCR from a friend of my uncle who had driven it from new, so I was sure it was a good investment. It cost me 1.5 lakh (about ?500). Clearing the debt is an uphill struggle. Since the fares are fixed by the city fathers at a rate even the poorest can afford - between 1 and 3 rupees (50 rupees = ?) - Shami will be carrying fares for 16 hours a day, 7 days a week for some time to come.

He seldom spends much time at home with his wife and children, preferring to sleep in the back of his machine. "It means I get one of the first runs in the morning which is always full. If I have a full load first thing it will bring me good fortune for the rest of the day." When he does see his family it's when they climb in for a ride into town. In this city of 10 million, everyone seems to meet on the road.