The book appears to be two stories, told in alternate chapters and set in different type.
One is the story of Ritwik Ghosh, a young man born in Calcutta around 1970. It begins with his childhood in an extended family. (No need to remember the many names and relationships - they soon disappear.) Ritwik's mother is an unbelievable sadistic disciplinarian; but both his parents die when he is 21. At the age of 23, he wins a scholarship to Oxford, and determines never to return to India. He regularly cottages in the public lavatories in Oxford; the descriptions of this activity are graphic and prolonged. When his student visa runs out, he stays in England illegally. He becomes the lodger and carer of an 86 year-old widow, Anne Cameron, who had once lived in India but was now living in Brixton. The descriptions of this lady - her mind often wandering, but at other times suddenly very lucid - are superb, as is the tender way in which Ritwick looks after her. But at times he also earns some money by doing back-breaking work during the day on fruit farms, exploited alongside other illegal immigrants, while on some evenings he rents himself out by cruising, dangerously, in the King's Cross area.
The other story is set in Bengal, mainly during the turbulent period between 1903 and 1905 when the British Raj was dividing the country between Western (mainly Hindu) and Eastern (mainly Muslim) Bengal, to the fury of the Hindus. The central character here is Maud Gilby, who is employed as "governess" (tutor) and companion to the wife of a Hindu landowner presiding over a largely Muslim village.
We are well into the second half of the book, on page 201, before we get a hint of what the link between these two stories might be - but that first suggestion is misleading; only later we gather from a couple of throwaway lines what the real link is. But at least I found here a possible explanation why the style of the second story is at times rather stodgy and lacks the brilliance of the first story.
There are occasional touches of surrealism in the novel - such as the appearance of brilliant oriental birds perched on a tree in a Brixton garden.
Mukherjee packs a lot of different stories into this his first novel, and though each of them is interesting in itself, I think they do not properly cohere. Many critics obviously think otherwise: the book was the winner of India's premier literary prize in 2009.