Under an off-putting title, mired in academese, comes one of the most arresting modern art shows of the year. ‘The Imaginary Institution of India’ takes its cue from an obscurantist essay of that name by the intellectual historian Sudipta Kaviraj, published in 1992 in a volume called Subaltern Studies VII. His original insight, buried in woolly prose, was that nations are fuzzy, precarious things, given territorial and ideological shape by the winners of history and contested by its losers, typically to little avail.

Certainly, there were losers galore in the turbulent quarter-century covered in this exhibition, bookended by the declaration in 1975 of the so-called Emergency – the Congress ruler Indira Gandhi’s preferred euphemism for what was, in fact, a dictatorship – and the nuclear test of 1998, overseen by the Hindu nationalist Bharatiya Janata Party (BJP) on assuming power for the first time. The victims of the former included the 11 million men and women forcibly sterilised in the name of ‘family planning’ – the flagship programme of the prime minister’s son, Sanjay Gandhi – not to mention the thousands of journalists and political opponents arrested as the freest society between Berlin and Sakhalin imposed strict censorship and suspended human rights.

Curiously, while some elite figures and a section of the working class were putting up a spirited defence of democracy, the middle classes greeted the regime with approval. Indira Gandhi, it was often said, ‘made the trains run on time’. A similar boast, incidentally, used to be trotted out by Mussolini’s votaries in Fascist Italy. What’s more, strikes vanished in Emergency India. Inflation was rolled back. In Delhi, the inner-city poor were carted off to distant banlieues by Jagmohan, city planner and Baron Haussmann fanboy, to make room for gentrified developments to house the chauffeured classes.

Most people she knew at the time, the political reporter Tavleen Singh wrote in her memoirs – which could just as well have been titled Reflections of a Nonpolitical Woman – were either indifferent or passively supportive of the Emergency. Accordingly, they retreated indoors: ‘my social life seemed to become an endless series of dinner parties’. It is this milieu that the Baroda artist and art historian Gulammohammed Sheikh sends up in Speechless City (1975), an utterly empty street scene that serves as a trenchant indictment of bourgeois complacency. The Pair (1976) by Vivan Sundaram, Slade alumnus and Marxist, is a more explicitly political picture, depicting Indira and Sanjay Gandhi as two ghoulish machinic figures, as if something dreamt up by Deleuze and Guattari.

Most of the artists here were socialists, if not outright Marxists. Thankfully, though, there is nothing doctrinaire in their pictures. Even the everyday canvases of Gieve Patel and Sudhir Patwardhan, both men of medicine moonlighting as artists in Bombay, are no dreary exercises in social realism. There’s a touch of Tiepolo in Patel’s delightfully mannered Two Men with Handcart (1979), the titular subjects enshrouded in the pink haze of a Bombay dusk.

Patwardhan’s The City, painted the same year, likewise elevates the mundanity of its subject with a finely observed detail. At the outset, our attention is drawn to a cultural quirk of the Indian working class: in time-honoured blue-collar tradition, the man in the centre is slurping his tea from a saucer, treated not as a fussier coaster as in England but bequeathed with the function of expediting the cooling of the beverage. A closer look reveals his eyes to be closed, thus transforming an ordinary scene into a meditation on an early morning ritual – the moment of calm before the day must be braved.

The show’s curator, Shanay Jhaveri, has done a splendid job reconstructing the Indian art scene in the closing decades of the 20th century, giving us a potted history of the period to boot. All the major set pieces are paraded before us: the assassination of two prime ministers, in 1984 and 1991, over sectarian strife; two pogroms, one against the Sikhs in 1984 and the other the Muslims in 1993; the millworkers’ strike of 1982 (the world’s biggest), the Bhopal gas tragedy of 1984 (the world’s deadliest industrial disaster) – this being India, superlatives come easy. The devastation wrought by the latter was captured with agonising effect by Pablo Bartholomew, whose heart-rending photograph of a half-buried child, eyes wide open, won him the World Press Photo of the Year. The executives of the American chemical company Union Carbide, charged with the culpable homicide of at least 25,000 people, never faced trial in India.

These and other injustices are handled with sensitivity in the show. It’s a shame, then, that Jhaveri time and again falls prey to the extravagant propaganda of Indian nationalists. There are some real howlers here, as when the nuclear test of 1998 is explained as the point ‘when the country relinquished its non-violent ideals’. That’s one way to describe a country with a long record of interventionism: three wars with Pakistan, one with China; the sordid boots-on-the-ground caper in Sri Lanka; to say nothing of the grubby record (sexual violence, extrajudicial killing) of the Indian army in the disputed borderlands. Besides, India had already tested the bomb before – in 1974.

The faux pas points to a broader defect: hopelessly enamoured of the Congress party, the curator is unable to think critically about its record. One can almost hear historians grinding their teeth in exasperation at the gushing account of Nehru’s India. ‘The project of social transformation’ spearheaded by the Congress, we are told, was abandoned by the unruly coalitions that replaced it in 1977. In truth, the Congress was the party of the upper castes, in hock to capital and landlordism. It was the coalitions that broke this monopoly, bringing the lower orders to power for the first time. The same impulse to shield the Congress accounts for a curious curatorial elision. We are shown MF Husain’s depiction of the killing of the communist playwright Safdar Hashmi (1989) during a performance in industrial Ghaziabad. What we are not told, however, is that the man behind the murder was a Congress politician.

Still, there’s much to commend, especially when the party line is abandoned. Women, Dalits, and homosexuals, denied their commensurate share in national life, get top billing here. The star of the show, inevitably, is Bhupen Khakhar, whose Two Men in Benares (1982) cross priapic swords against an ultramarine backdrop brimming with pious figures, as in the frescoes of the Sienese master Ambrogio Lorenzetti, whose effects Khakhar consciously emulates. Equally vivid are Sunil Gupta’s snaps of men cruising in Delhi’s dogging spots. Then we have the etchings of the Dalit painter Savindra Sawarkar, no less hard-hitting for being heavy-handed, channelling the energy of the Dalit Panthers, who railed against that ‘motherfucker god of the Brahmans’ for laughing shamelessly in the face of ‘Untouchable despair’.

Finally, we have Sheba Chhachhi’s portraits of the women who took up the cudgels for gender equality. The image that stayed with me is the one of Sathyarani, defiant and tough as nails, draped in a sari on the footsteps of the Supreme Court, reams and reams of documents at her feet, waiting patiently for her son-in-law, who burnt her daughter to death for an insufficient dowry in 1979, to get his just deserts. As it was, it was only in 2013 that he was handed a sentence of seven years.

In India, to be sure, the justice system leaves a lot to be desired. Happily, however, the same isn’t true of artistic production in the country. For all the grim material on offer here, this is a most uplifting show.

The Imaginary Institution of India: Art 1975–1998 is on at the Barbican until 5 January 2025.