Two nations, 22 events in 7 days

The couple will stay at the Taj Palace, once the target of terror attacks. Photo / AP

Her home is a 2.5m by 2.5m room shared with her parents and six siblings, so the question Indian slum dweller Saniya Puniya Chauhan wants to ask the Duke and Duchess of Cambridge is perhaps glaringly obvious.

"How can they live in such a big house?" mused the 10-year-old as she prepared to meet the royal couple in Mumbai. "How do they communicate?" she went on. "How do they call each other? "

William and Catherine can expect to be bombarded with similarly frank questions from some of the world's poorest children on their seven-day day tour of India and Bhutan.

It promises to be their most varied foreign trip to date, ranging from grinding poverty in Mumbai to the majesty of the Taj Mahal, and taking in a red-carpet event, a safari in Assam, a pilgrimage to Gandhi's home and a trek to a Himalayan monastery.

First they were to lay a wreath to the victims of the 2008 terrorist attack on the Taj Mahal Palace Hotel in Mumbai, then see the work of three children's charities at a slum, before rounding off the day with a charity gala dinner to raise money for the same charities, where celebrity guests will include the "Queen of Bollywood", Aishwarya Rai Bachchan, and cricketing legend Sachin Tendulkar.

Anmer Hall, their home in Norfolk, could comfortably be divided into more than 100 typical dwellings in the Babasaheb Ambedkar Nagar slum, where Saniya lives, meaning the property would be home to upwards of 500 people, rather than four.

The comparison has clearly crossed the minds of Saniya and other pupils at the slum's Door Step School. Many start work at the age of 7, gutting fish or scavenging rubbish dumps for 3 a day, and drop in to the school in the evenings to learn how to read and write.

The Duke and Duchess, who are travelling without their children, are packing 22 engagements into just seven hectic days.

William, now three years older than his mother was when she visited the Taj Mahal, wants to "create new memories" of the place that has come to symbolise the failure of his parents' relationship, according to his staff.