It was a cruel joke – sitting in gridlocked traffic on a steamy Bombay night two signs mocked me: “Reduce road congestion, travel BEST” implored one public transport ad; “AirTel” screamed the other. Air I was definitely lacking in the Bombay smog. Traffic congestion – I had that in spades.

Taking another bite of Bombay’s atmosphere I stared out the window of my beaten up taxi. From here it was clear the city had a definite hierarchy to its vehicles, a sort of motorised caste system. We were all on the same road, but some of us were doing better than others.

At the bottom of the heap sit the auto-rickshaws – the three-wheeled mini-transport familiar across Asia. Cheap, plentiful and open to the elements; anyone inside is exposed to the full range of the city’s many and varied particulates and noxious gases. Half an hour in one of these and you may as well give up smoking – why spend the cash on fags when you’re getting all that crap included with the fare. Banned from the city centre, they’re cheap, plentiful and the lifeblood of transport in the northern suburbs.

Next up are the taxis and like much of the caste system these have their own sub-divisions. The lower of the two classes are the battered black-and-yellow jobs that ply the streets in the same way the autos do. With no air conditioning passengers are left with two choices: leave the windows down to get some (relatively) cool air into the vehicle – along with the various airborne toxins – or wind them up (assuming they work) and proceed to broil while stuck in the same traffic jam as the auto rickshaws. At least in the taxi the interiors provide some diversion: they range from those without a dashboard and seats that feel like there’s wildlife underneath, to ones that have been decorated with what appear to be off-cuts from a rug showroom and seconds from a chandelier emporium.

In the same caste but of infinitely higher status are the air-conditioned taxis. Safely locked inside one of these it’s easy to forget about Bombay’s traffic jams as the cool, clean air wafts around the car. It’s pure bliss after the exposed hell of the lower rungs and traffic jams become a mild inconvenience, rather than something that may require a lung transplant. Significantly more expensive than the previous two options, they are not an every-day transport mode for much of Bombay.

Even less available to the masses – although there are still masses of them – are the private cars; SUVs and sedans that can be found sitting outside shopping malls and restaurants with their drivers inside while the owners shop, eat and drink. These metal and glass bubbles ensure the owners move from air-conditioned apartment to air-conditioned shopping mall and back in air-conditioned comfort. The better off you are in Bombay the less you have to deal with the city and if you’ve got your own vehicle with driver, you’re clearly reaching the top of Bombay’s ca(r)ste system.

But the pinnacle, those who have attained auto-moksha, are those sitting in the car next to me in the sweltering Bombay traffic. Inside the white Ambassador sedan sit MPs, government officials or military brass on their way across town. With their red sirens and twee, white lace curtains, these cars perhaps represent the ultimate in getting around Bombay; the top of the tree, release from the car-mic hell of the city’s roads. While perhaps not as comfortable or expensive as the private cars plying the roads, they do have one major advantage – someone else is paying for the trip.