The train is packed, the passengers, squashed together with boxes snug between their knees, don’t seem to notice – they are too engrossed in a game of bridge. Elsewhere, other riders have found another way to have fun, singing and playing instruments.

These sights, quite unimaginable in Singapore, are common in the Mumbai suburban railway, which carries over 7 million passengers from all types of socio-economic class every day.

“Whether you’re rich or poor, you’re forced to use the [Mumbai subway] because it’s the fastest way to get from point A to B,” said economist and environmentalist, Mr Sanjeev Sanyal at a recent talk organised by the Centre for Liveable Cities.

It is his proposition that as a result of such constant interaction between its rich and poor, Mumbai, despite the massive wealth disparities, is one of the most egalitarian cities in the world.

Named a “Young Global Leader” in 2010 by the World Economic Forum, Mr Sanyal is founder and president of the Sustainable Planet Institute, a think tank and innovation centre based in New Delhi. Born in Calcutta, he now lives in Singapore, where he is a global strategist at Deutsche Bank. Author of Land of the Seven Rivers: A Brief History of India’s Geography and The Indian Renaissance: India’s Rise after a Thousand Years of Decline, Mr Sanyal has also worked closely with officials worldwide on urban planning.

Most city planners, he tells Challenge, assume that a rapidly growing city must first plan the roads for cars and then create the pedestrian network. He challenged that assumption: “Technology will keep changing the [types] of transport [we have] but so long as cities are built for people, they will walk in them.”

What’s “walkability”?

So what does the Mumbai train system have to do with the “walkability” of the city?

A “walkable” city is one where walking is an important, if not the dominant, mode of transport for the average citizen, said Mr Sanyal.

“Walkability” is not just about the act of walking itself because obviously, you would need to go much longer distances than you could walk.

That’s where public transport matters. “Every form of public transport is based on walking, because the first and last miles have to be walked, unless you’re very lucky and have a bus [or train] stop right in front of your door. So designing [a city] for public transport … is essentially about designing for walking,” he said.

In other words, think of walking as the flexible backbone of a system of getting around a city – it can be “mixed and matched” with various modes of public transport to enable people to navigate the city effectively.

Mr Sanyal cited New York as another example of how, in his opinion, “walkability” has helped to foster relations between the haves and have-nots. “It is a city where both the rich and the poor walk on the same sidewalks and stroll through Central Park. That is why New York has a very egalitarian and inclusive feel, despite having very high income inequality.”

Measuring “walkability”

Mumbai and New York are two of about 20 cities he has walked through extensively for the past five years. Based on his experience, he rated these cities using his own “Walkability Index”.

The index looks at a variety of factors – pedestrian infrastructure (pavements, shades, signage); the effectiveness of connecting walking with other modes of transport (buses, trains, bicycles); amenities like cafes and parks that encourage interaction; and safety. “Walkability” is more than creating more sidewalks, he emphasised.

What about weather? Shouldn’t that be an important consideration in the “Walkability Index”?

Not to Mr Sanyal, who explained wryly: “Every city I go to, everybody who lives there says, ‘The weather is not conducive for walking.’ In Singapore, it’s too hot and humid… In London, it’s always drizzling. So I’d just assume that every city is equally ‘unwalkable’ from the weather perspective.”

The top spot on his list belongs to Zurich, thanks to its excellent tram and train network, and its free bicycle rental system that makes it a breeze to cruise around the city (for more information about other cities on his list, listen to his speech at bit.ly/sanjeevclc).

How does Singapore fare?

Singapore comes in at a close second. Mr Sanyal credited the high ranking to an “intelligent urban policy that uses both carrots and sticks”. While the high prices of cars have kept car ownership “very low” for a country with Singapore’s per capita level, the country’s heavy investment in pedestrian infrastructure and public transport connectedness has paid off handsomely. A high level of overall street safety also makes Singapore one of the most “walkable” cities in the world.

A minor blight on Singapore’s stellar report card is the “horrid” taxi system. “The biggest problem for walking in Singapore is not the heat or the sweating, but the rain. Whenever it rains, the taxi system breaks down,” he said.

Mr Sanyal hopes that Singapore would consider boosting cycling as a more viable mode of transport. He cycles from his home at Tanjong Rhu to work at One Raffles Quay, passing by Gardens by the Bay and the Marina Barrage.

He was also critical of the closing of the Orchard-Patterson pedestrian crossing to ease car traffic. Now pedestrians wanting to cross the two roads would have to look for the underpass at the Ion Orchard shopping mall and find the Ion-Patterson link. This can be a challenge, given the lack of signage.

“I’m a reasonably good walker and I know my way around. It still took me 4.5 minutes to get to the other side,” he said. “Why should one walking be spending that 4.5 minutes [going] up and down? If anybody should have to do it, [it is those] in the air-conditioned cars!”

He stands firmly by his belief that ensuring “walkability” – building the city for people, not cars – is the way to go in planning successful cities.

“I keep telling people that a sign of prosperity is not that the poor drive around in Ferraris, but that the rich walk. Thankfully, I think that message is getting through to some cities.”