Inside the rise of slum tourism. Can it really be a mutually beneficial experience?

When the Duke and Duchess visited Mumbai earlier this year, their royal visit schedule was perhaps nothing out of the ordinary.

A tour of New Delhi, then to Mumbai's Taj Mahal Palace while checking into India's most luxurious five-star hotels.

And then, to perhaps balance the extravagance and their conscious, the couple visited the Banganga slums in Mumbai.

The Royals during their tour in April

They played cricket with a handful of the thousands of street children who call the place home, visiting locals as they went about their day.

It was all very, well, compassionate and nice and smiley. There was lots of smiling.

And that's possibly why Wills and Kate aren't alone in their quest to polish their goodwill credentials.

In fact, since 2014, there's been a sharp rise in slum tourism, also known as "slumming" or poverty tourism.

Travellers search out organised tours to visit slums around the world. A few in India, then Johannesburg and Rio de Janeiro.

According to estimates by a group of researchers who penned Slum Tourism: State of the Art, over one million tourists visited a township, favela or slum somewhere in the world in 2014.

The likelihood is that this figure is even higher, with even more gap year students signing up to work for charities in the poorest corners of the world.

In Germany and the US, state sponsored programs exist to funnel young people into volunteering jobs abroad.

It's all very altruistic. So, why does it feel a little unsavoury? Ultimately, it's probably because the attraction is poverty.

But it shouldn't be overlooked as just an afternoon of mutual gawping at "how the other half live".

The key here is to research. It's important to handpick tours which are run sensitively, with a tour guide from a humble background who has the blessing of community representatives.

And organisations should be pushing most of the profits back into local charities. Probably aim for above 75 percent.

And it is important to go through an organised tour, especially in areas in Rio which are extremely dangerous.

Also, a note on behaviour. Leave your selfie stick and your peace signs at home. This isn't a novelty photoshoot to put on Facebook.

But the biggest advantage is awareness about the divide between the rich and the poor, away from the luxe lights of the county's five-star resorts.