What national development are we talking of when close to 600 million people in India do not have the basic amenity of a toilet?
But in terms of public toilet provision, the family is well-served compared with other areas, with an adequate communal block a five-minute walk away near the US Consulate and another under a busy road in the opposite direction.
In slum areas, where more than half of Mumbai lives, an average 81 people share a single toilet. In some places it rises to an eye-watering 273. Even the lowest average is still 58, according to local municipal authority figures.
Unsurprisingly, it is still common to see people squatting by roads and railway tracks or along the coast, openly defecating in the city that drives India's economy and where some of the world's richest people live.
The UN estimates that 600 million people or 55 percent of Indians still defecate outside, more than 60 years after the scrupulously clean independence leader Mahatma Gandhi first talked of the responsible disposal of human waste.
Jack Sim takes a very keen interest in such matters. As the founder and president of the World Toilet Organization (WTO), he has made it his mission to improve sanitation across the globe.
For him, India has "a lot of work to do" to improve sanitation, not just because of its impact on health and the spread of diseases like diarrhoea, which UNICEF says kills 1,000 Indian children aged under five every day.
It also tarnishes the image of a country that likes to portray itself as an emerging world economic superpower, the Singapore businessman told AFP on a visit to Mumbai, where he was promoting World Toilet Day on November 19.
In particular, Sim questioned whether the authorities in New Delhi were doing enough to provide adequate public toilet facilities for the 2010 Commonwealth Games, which will draw tens of thousands of foreign visitors.
"If you don't have good toilets to welcome tourists, they don't come and won't go to all your beautiful sites," he said.
Public toilet provision in Mumbai -- and other cities -- faces the same problem affecting housing, water and other basic services: supply cannot keep up with demand as India's population explodes.
In March, Mumbai's municipal authorities said there were 77,526 toilets in slum areas and 64,157 more were needed. Work is in progress on only 6,050.
Yet the UN's Mumbai Human Development Report 2009, published earlier this month, points out that even where public toilets exist, most have no running water, drainage or electricity, making them unhygienic and unusable.
Embarrassment means women and girls often wait all day until it is dark to go to the toilet, increasing their chances of infections and exposing them to violence or even snake bites as they seek out remote places.
Poor sanitation and the illnesses it causes cost the Indian economy 12 billion rupees (255 million dollars) a year, according to the health ministry.
Sim, who sees links between public lavatories and social development, wants the issue pushed up the political agenda, urging people to "talk more about toilets."
"People go to the toilet more often than they have sex," he said. "Everybody has to go.
"It needs to be a very nice experience. It needs to be safe, it needs to be hygienic, it must not cause problems to your health and we need to feel emotionally engaged with the toilet."
Private sector involvement could help cut the number of people in India and other developing countries who have no sanitation -- estimated at 2.6 billion -- while more schemes are needed to make open defecation socially unacceptable, he said.
In Haryana state, north India, a successful "No Toilet, No Wife" campaign has been running, urging women to turn down suitors if they cannot provide them a house with a lavatory.
"Every problem is a business," said Sim, adding there would be a benefit for the entire city and the country's economy if every slum-dweller had access to proper sanitation.
"People who are healthy are able to produce more, they get out of poverty, they get into the middle class, they move up and consume more," he said.
"Business is, I think, the fastest and the cheapest way... The private sector will come up with innovations. Let them compete to serve the poor."