The horrific gang-rape is as much a part of the story of change in this vast and complex nation as the impressive creation of wealth or the country's famous infotech industry. It has, however, laid bare the dark side of India's growth story.

First there is the acutely unhappy coexistence of mutually incompatible social norms: those of a deeply conservative patriarchal rural society and those of a modern urban city where hierarchies that have been in place for centuries are fast breaking down. As an editorial in the Mint financial newspaper put it last week: "India is currently in a twilight zone when the traditional social norms have lost their resonance while modern values based on individual liberty have not yet gained acceptance."

Urbanisation has brought the two cultures together in an unprecedented way. The six men accused of the attack grew up in villages where rapes, which happen with frightening regularity, are dismissed as a risk teenage girls run, an extension of the activities of young men doing what young men do.

A second element is a continuing inability to see women in any role other than mother, child or spouse. Indian media have persistently referred to the rape victim as the nation's "daughter". Even in death she has been confined to one of these three categories. But a modern economy needs and creates women who are independent.

A third is the violence so endemic in so much of India. Alongside the dozens of rapes discovered by reporters last week across the country, local newspapers reported a tea planter burned to death in Assam and an alleged petty criminal blinded with acid by villagers. Delhi is a particularly rough-edged city where the aggression stains the most mundane of normal social transactions. A policeman strikes a shopkeeper for talking back; traffic gives way to the biggest, most belligerently driven vehicle; a teenage girl is shot dead for telling a drunk not to urinate on her front door.

Violence contaminates relations between sexes from the start. Hundreds of thousands of female foetuses and infants each year are killed because they are not male. One poll last year found that around two-thirds of Indian men surveyed thought women needed to be beaten.

Much of this violence is linked to the tensions generated by change. This is compounded by the extraordinary isolation of the political elite, which has remained locked in the 1920s in terms of accountability, transparency and communication.

The response of the ruling centre-left Congress party to the protests was silence and teargas. "Our model of policing is colonial," a senior officer in south Delhi explained. But the colonialists left India 65 years ago and the country has moved on.

It is this that tempers this otherwise dystopic vision. This week, tens of millions have made their outrage and grief clear. They are representative of a different India, one much closer to the image of the country overseas, and as change continues in India their voices will grow louder every day. But they have a tough fight ahead of them.