Social realism can be defined as works that present racial and social injustice and economic deprivation through a presentation of characters who are facing such issues. By so doing, social realism protests against such inequalities and injustices. When we consider this in the light of this excellent novel, it is clear that Roy is using social realism to critique a number of different aspects of the contemporary world, including the caste system that is still in operation in India, colonialism and corrupt officials. However, one aspect that I found particularly striking is the reality of immigrants who leave countries such as India and go to "richer" and more developed countries to supposedly enjoy a better quality of life. Consider how this works out for Rahel when she goes to the United States:

After they were divorced, Rahel worked for a few months as a waitress in an Indian restaurant in New York. And then for several years as a night clerk in a bullet-proof cabin at a gas station outside Washington, where drunks occasionally vomited into the money tray, and pimps propositioned her with more lucrative job offers. Twice she saw men being shot through their car windows. And once a man who had been stabbed, ejected from a moving car with a knife in his back.

The "reality" of so many immigrant dreams of attaining wealth and employment is that they end up doing the kind of jobs, like Rahel, that no American wants to do themselves, living lives of relentless hardship and confronting the evils of a society that is supposedly "developed." You might like to think about this as a theme and how social realism operates in presenting such aspects as immigration in the novel.

I think that one element of social realism that is present in Roy's work is how political and authoritarian establishments do not necessarily work for the best ends of the people.  These organizations do not empower individuals from the top down, as much as they seek to control individuals and consolidate political power for personal ends.  Roy depicts a structural vision of power that does not seek to enhance autonomy as much as limit it.  In this light, there is a definite statement being made on the nature of political power in India and how it needs to be changed in its effects on people.  This is not merely governmental, as Roy's social realism is depicted in the stratification of both race and caste terms.  There is a definite socially realist aspect presented in the relationship between Ammu, part of the new generation, and her father, reflective of the old one and its relationship to the British.  At the same time, the demarcation of untouchability was crossed over by Vellya Paapen's son, something that he must restore through murdering his own.  In this light, the social reality is that division and stratification again seek to limit human interaction and autonomy.