Dinesh Mohan retired as Emeritus Professor at the Centre for Biomedical Engineering at the Indian Institute of Technology, Delhi in 2015. He was previously the Coordinator of the Transportation Research and Injury Prevention Programme at IIT Delhi. He is a recipient of the Distinguished Alumnus award from IIT Bombay and the International Distinguished Career Award from the American Public Health Association. Mohan’s research has been on transport, human tolerance biomechanics, motor vehicle safety and road traffic injuries.
On 21 December 2015, Harper Sutherland, an intern at The Caravan attended Mohan’s talk “Thought Experiments in Moving around Cities” at the India International Centre in Delhi. He discussed the argument for limiting road space for traffic, the importance of congestion and the lack of accurate data regarding pollution and motor vehicles.
The situation we face in Delhi today is horrible pollution. And we start by comparing Delhi to Singapore, to New York, and to many other cities which are on the coast. If you’re going to compare Delhi with any other large city, you’ll have to compare us with other landlocked cities. Because landlocked cities’ air, and what happens in those landlocked cities is very different from cities on the coast. Or with very, very large rivers around them.
The problem is that when you look at traffic, you think of it as just vehicles moving from one place to another. But actually, traffic has a huge amount of effect on our health. Congestion is the least of our problems. Congestion is a market response to a place being good. The reason places get congested is—that’s where people want to go. You should be really happy that a place is congested. If it is not congested, then no one wants to go there.
So coming back to the pollution in Delhi: how do we calculate what is causing pollution in Delhi? There are two approaches for finding out what is happening. One is a bottom-up one, and the other is top-down. Bottom-up is a source inventory, in which you take everything that causes pollution, so you have vehicles, stationary generator sets, bulldozers, cooking sources, power plants, brick kilns, fires, road dust, etc. Then you find out how many of those are there in the city. What’s very interesting is we don’t know the exact number of vehicles being used in Delhi. Fires; we say “don’t burn this, don’t burn that.” We don’t know how many fires come out in the evening. We say, “you’re not allowed to burn wood or leaves.” Then what is the chowkidar going to do; do you give him a heater to sit the whole night? So we have the Supreme Court and other courts, and administrators just adding edicts, that you can’t do this, you shouldn’t do that, without finding a solution. That’s why it doesn’t work. Our calculations for road dust for road dust are also rough approximations. We have very rough estimates for all of this.