Arundhati Roy’s literary career has been one of a kind. Thrust into the limelight of the global publishing industry back in 1997 when her debut novel, The God of Small Things, won an advance of half a million pounds and then the Booker prize, she might have gone on to become a household name of cosmopolitan novel writing in the way that Salman Rushdie and Kazuo Ishiguro had in the decades before.

Instead, she steered clear of the form altogether for the next 20 years (until the 2017 publication of her follow-up novel, The Ministry of Utmost Happiness), devoting her attention and profile in the meantime to prose nonfiction that has energetically uncovered skeletons in the closet of India’s economic growth story: the nuclear arms race with Pakistan; the thousands of indigenous people displaced by the Narmada dam project; the Maoist insurrection across the country’s tribal heartlands; and the issue of Kashmir’s longstanding and brutal military occupation.

No stranger to controversy, this choice of subject matter, poking around in the hinterlands and shadowlands of 21st-century India, has kept her on a path of constant collision with the establishment at home. Roy’s engagement with Kashmir in particular, including her explicit support for Kashmiri separatism, for example, led to her being accused of sedition in 2010.

In spite of what she describes in Azadi, her latest collection of essays, as an atmosphere of “continuous, unceasing threat”, Roy has refused to back down and this volume, which takes its title from the Urdu word for “freedom” – azadi is the chant of Kashmiri protesters against the Indian government – serves to keep the Kashmiri situation in the minds of her global readership.

“What India has done in Kashmir over the last 30 years,” she writes in the essay The Silence Is the Loudest Sound, “is unforgivable. An estimated 70,000 people – civilians, militants and security forces – have been killed in the conflict. Thousands have been ‘disappeared’, and tens of thousands have passed through torture chambers that dot the valley like a network of small-scale Abu Ghraibs.”

Azadi, which builds on the 1,000-page edition of Roy’s collected nonfiction, My Seditious Heart (published in 2019), consists of nine stand-alone essays, written between early 2018 and early 2020 and originally delivered either as lectures or long-form print pieces, often in Britain or the US. Roy writes repeatedly in response to Hindu fundamentalism’s new hegemony in India, exemplified by the second electoral victory of Prime Minister Narendra Modi.

In Intimations of an Ending: The Rise and Rise of the Hindu Nation, for example, she reads the growing popularity of Hindutva, its strategies of warmongering and scapegoating and the autocratic style with which Modi governs as, very plainly, a kind of fascism, a kind of “tin-pot authoritarianism” that resembles, according to her, the dysfunction of Nazi Germany.

She calls out what she sees as the absurdity of a “doctrine of One Nation, One Language, One Religion, One Constitution” being imposed on a region that is “not a country”, but rather a “continent” – “more complex and diverse, with more languages – 780 at last count, excluding dialects… than all of Europe”. Conversely, Roy’s writing is in defence of multiplicity. The India she wants us to grasp, is a “vast ocean”, a “fragile, fractious social ecosystem”.

The passion and beauty of her voice is unabated, but what comes through in this volume, too, is a new sense of maturity in both her execution and engagement as she comes to terms with her vocation and the choices she has made. “I have often caught myself wondering,” she writes in The Graveyard Talks Back, “if I were to be incarcerated or driven underground, would it liberate my writing? Would what I write become simpler, more lyrical perhaps, and less negotiated?”

The startling wisdom that Roy unveils in response is this: “I believe our liberation lies in the negotiation. Hope lies in texts that can accommodate and keep alive our intricacy, our complexity, and our density against the onslaught of the terrifying, sweeping simplifications of fascism.” What she has produced, in Azadi, is precisely such a text – the outcome of a life of writing from the frontline of solidarity and humanism, and from a writer who is perhaps only now reaching the height of her literary powers.

• Azadi by Arundhati Roy is published by Penguin (£6). To order a copy go to guardianbookshop.com. Delivery charges may apply