India is the world’s largest democracy. In this year’s national election, which was staged over seven phases from April to June, nearly 650 million voters cast their ballots. Democratic rituals, for all their flaws, seem so profoundly to be embedded in the Indian political landscape that it can be easy to overlook the country’s experience of brutal authoritarian rule. Narendra Modi’s erosion of democratic institutions is not so much a novelty as an informal reprise of Indira Gandhi’s rule less than half a century ago. In 1975, faced with sustained labour strikes, mass protests on the streets and a court ruling disqualifying her from holding public office, Mrs Gandhi suspended the constitution and declared a state of internal emergency. Her opponents were thrown in prison and the press was censored. This was the soft aspect of her rule. The truly harrowing story unfolded in the villages and towns, where the prime minister’s son, Sanjay, fixated on curbing India’s population, launched a mass sterilisation programme. More than six million men were subjected to forced surgical procedures in one year: some were mutilated. Sanjay’s drive to beautify India’s cities resulted in forced displacement of innumerable people. In Delhi, the police opened fire on the residents of a slum who attempted to resist peacefully. The memory of the “Emergency” – as the period is universally remembered – can still make people shudder today. The Imaginary Institution of India, opening at the Barbican in London, uses the declaration of the Emergency in 1975 as a starting point of the story of India’s voyage through decades of political tumult, culminating in the country’s successful nuclear test in 1998 – an event that, following extensive condemnation by western powers in possession of vast nuclear arsenals of their own, led to India being described as an “emerging great power”. The artworks on display – forged in a period of social instability, sectarian strife, state-sanctioned violence, history’s worst industrial calamity at Bhopal, followed by economic liberalisation, a proliferation of wealth and intense urbanisation – vivify India’s extraordinary metamorphosis. This transformation supplied a new stimulus to artists. The show hauntingly illuminates the civic engagement artists and Indian society took part in while, rattled by the Gandhi family’s abuse of power, they reckoned with the reality of the terms of their nationhood. Indira Gandhi’s assault on the constitution had the effect of intensifying individual and collective activism, which confronted the establishment subtly from the studio and stridently from the street. The artist and poet Gulammohammed Sheikh painted one of his first political artworks, Speechless City, in response to the excesses of the Emergency. Post-apocalyptic in its vision, India’s urban landscape, ordinarily overrun with all forms of life, is emptied out. Stacks of jaunty modernist housing, swaddled in an ominous saffron hue, show no trace of their inhabitants. Doors and windows are left ajar, and feral dogs and flocks of birds scavenge the cityscape. The image, from 1975, looks remarkably prescient today. The fiery pigment, a colour associated with the Hindu right, seems to radiate a warning of the coming communitarian violence that was to erupt with fury in the 1980s and the early 1990s. The 1980s was an especially violent decade. The combination of crises – militant separatist movements, militaristic responses by the state, the assassination of Mrs Gandhi in 1984, and the pogrom of the Sikhs that followed in Delhi – seemed to shatter the cultural and religious syncretism held up by Jawaharlal Nehru and Mahatma Gandhi as a core tenet of the modern Indian republic. Artistic concerns went beyond religious division and addressed the perilous status of India’s marginalised groups. The experience of queer communities, criminalised in law and stigmatised by society, were piercingly evoked in Bhupen Khakhar’s vivid paintings, in which early Renaissance perspectives folded into miniature flatness, and tender photographs by Sunil Gupta. Gieve Patel and Sudhir Patwardhan considered daily wage workers, while others, such as Jangarh Singh Shyam brought to the fore and innovated indigenous visual culture. These depictions, when put on display, tended sometimes to incite the very forms of oppression they sought to expose. Khakhar’s portrayals of intimate same-sex embraces, for instance, had to be hidden to maintain the peace. Savindra Sawarkar not only addressed India’s caste system but also centred Dalit communities (formerly Untouchables) – making him a pioneer in an art world that was still dominated by the upper castes. In his etchings from the mid 80s, Dalit figures forged from a scratchy matrix of black lines, so dense that they appeared to be annihilating the individuals to which they gave shape, were shown with the brooms carried to sweep away their footprints and the pots fastened around their necks to collect their saliva, considered a pollutant by upper castes. The plight of India’s oppressed communities was thrown into agonising relief by the rape in custody, in 1972, of a teenage Adivasi girl called Mathura. The protests ignited by the acquittal of the policemen who raped her also became the spark for the women’s movement that crystallised by the end of that decade. The anti-dowry rallies, sit-ins and street plays that exploded in Delhi launched Sheba Chhachhi’s long-term photography project, which chronicled the activism of seven women between 1980 and 1991. “These women moved from their personal tragedies into the larger realm of changing conditions for women,” Chhachhi tells me. “Many of them are no longer with us. They were friends, but they live on in the work, and they offer that possibility of resistance and change.” Sathyarani – Staged Portrait, a photograph of a mother seeking justice for her daughter burnt to death over her dowry, encapsulates the sustained campaign for legal reform. The elderly woman, draped in a sari, sits on the stairs of the supreme court in Delhi, the stacks of files strewn before her a testament to her tenacity and the obtuseness of the system. The exhibition’s curator, Shanay Jhaveri, has attempted to follow each artist’s progression over the period covered by the show. The works he has chosen show aesthetic changes and realignment of practices in response to the events between 1975 and 1998. The sixth of December 1992, when the Babri mosque was razed by Hindu supremacists in full view of the authorities, is often regarded as a moment of rupture in the history of Indian art. Just as there was a before and after Duchamp’s Fountain, Indian art can be periodised into before and after this cataclysmic event. The riots that flared up across the country were captured extensively by a media culture that had transformed exponentially after the opening up of India’s economy the year before. Sheela Gowda, a formidable artist based in Bangalore, questioned her practice after seeing a photograph of fatal religious clashes in Hyderabad in central India. “I couldn’t continue in the same way,” Gowda told me. “The political was not being reflected in the paintings I was doing.” The artist Rummana Hussain abandoned painting altogether for performance and object-based installations which, including shards of smashed terracotta pots, alluded to the shattering of civic society. Gowda, searching for something “immediate and meaningful”, adopted a new material, cow dung, sculpting it into installations and applying it to paper. Dung, a material of utilitarian and spiritual value in India, also bespoke the contradictions in an increasingly fractured country. A surge of foreign investment generated explosive patterns of consumption in what the Indian economist Jean Drèze called “islands of California”, while most of the rest of India remained “a sea of sub-Saharan Africa”; most Indians struggled to make ends meet as food prices rose and the government pared back public investment to make up for the generous tax cuts it gave to corporations. The show’s chronology enables the audience to move through themes, but it would be inaccurate to regard the period it isolates as artistically unique. Art in India has long been inextricably linked to politics, and there is a lofty artistic tradition of engaging with social upheavals, not only at home but also abroad. In 1971, many Indian artists, including Khakhar, reacted forcefully to the Bangladesh war and the atrocities that gave rise to it. The drawings of Vivan Sundaram, another artist included in this show, are some of the sharpest artistic responses to the Gulf war of 1991. Despair, disillusionment and defiance leap from many of the works here. The show’s timing, staged just as India begins to settle into the third consecutive term of Modi’s strongman rule, seems fitting. India in recent years has been the site of some of the largest democratic protests in its history – from the women-led sit-in against the government’s introduction of a religious test of citizenship, to the farmers’ uprising that compelled Modi to reverse course, to the demonstrations by unemployed youth in a country where economic inequality is thought to have grown worse over the past decades than it was under the British Raj. The exhibition is a reminder that the struggle for human dignity is in fact a never-ending battle. The Imaginary Institution of India: Art 1975–1998 is at the Barbican, London, 5 October to 5 January