The main aim of the book is to show what a damaging effect colonisation has on both coloniser and colonised. The English appear generally cold and unbending towards the Indians, and behave with haughty superiority towards them. Of course there are notable exceptions like Fielding, and the two newly-arrived ladies, Adela and Mrs Moore, but even their relations with the Indians turn out to be less than straightforward. They attempt to form genuine connections with them, only for all sorts of social and cultural misunderstandings and barriers to get in the way – culminating in the trial of an innocent Indian man, Aziz.
Forster shows that many of the English out in India may actually be nice enough individuals in themselves, but unfortunately, when they are around Indians, the race-mentality kicks in and they generally become insufferable. Some of the English display racist prejudice of the worst kind, for instance Mrs Callendar with her notorious comment that: ‘Why, the kindest thing one can do to a native is to let him die’ (chapter 3).
On the other side, the Indians are also seen to be adversely affected by colonialism. They often present a rather ingratiating front to their rulers but mock and despise the English behind their backs. Of course, it is entirely understandable that they should be resentful of their self-imposed overlords, but they don’t really seem willing to get together to really try to do something about it.
Even Aziz, the most fully-realised Indian character, is seen to harbour some quite virulent racist tendencies and assumptions of his own, not so much towards the English (until later in the book) as towards other Indians: principally ‘flabby Hindus’, as he calls them (chapter 2). The Indians generally seem incapable of uniting effectively against the oppressors, in this novel.
Indeed, colonialism serves to bring out the worst in both ruler and ruled. Aziz’s trial of course is the dramatic high point of the tensions between the two races, but although Aziz is sensationally cleared, the Indians briefly united behind him, and the English temporarily discomfited, nothing is really seen to change as a result. The old misunderstandings and divisions go on.
The novel, then, deals with the detrimental effects of colonisation on the minds and actions of both ruler and ruled. It should be noted that the focus really remains on individual relationships and behaviour, rather than tackling the whole issue of colonialism per se. For instance, Forster never says anything at all about the whole economic side of colonisation, an omission for which this novel is often criticised. The English control vast swathes of Indian resources, but this really doesn’t figure in the novel as an issue.
To sum up, Forster's main interest is in how colonisation affects individual connections, and really only those in the higher, more educated ranks of society on both sides of the racial divide. He does not really show the effects of colonisation on the lower classes, who largely remain part of the picturesque backdrop to the novel.