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When the National Book Trust released Anna Mani: The Uncut Diamond this September, few expected a modest biography of an Indian meteorologist to stir such profound reflection about our age of climate anxiety.
However, Asha Gopinathan’s book has done just that by bringing back to public memory a woman who, half a century ago, had already begun documenting the atmospheric changes we now refer to as the Anthropocene.
Before the ozone hole became headline news or “climate change” became political currency, Anna Mani, a physicist from Kerala, clad in khadi, was quietly measuring the skies over Pune.
Each dawn in the 1960s, she climbed to the rooftop of the India Meteorological Department (IMD) laboratory, adjusting instruments she had built herself. Through glass tubes and Teflon pumps, she captured traces of a changing world: falling ozone levels, rising pollution, and the first fingerprints of human activity on the atmosphere.
In The Uncut Diamond, Gopinathan reconstructs Mani’s life with remarkable intimacy, from her childhood in the misty cardamom hills of Peermade in Kerala’s present Idukki district to her lonely battles in the corridors of a male-dominated scientific establishment.
Yet the book’s most striking contribution lies in its recovery of Mani’s ozone work at IMD Pune, research that made her one of the first scientists anywhere in the Global South to measure humanity’s impact on the air.
“She was far ahead of her time,” Gopinathan told Down To Earth (DTE). “Mani saw urbanisation not as progress alone, but as a force reshaping the chemistry of our skies.”
That prescience now reads as prophecy. Long before the Anthropocene became a buzzword, Mani had already recorded its arrival — through ozone columns and electrical conductivity readings above a growing Pune.
When Mani joined IMD’s Pune headquarters in 1957, atmospheric science in India was still largely descriptive. She changed that with methodical precision. By the early 1960s, she had designed the country’s first reliable radiation and solar measuring instruments, pyranometers and sunshine recorders, that could withstand India’s humidity and heat. But her most pioneering work began when she turned to ozone and atmospheric electricity.
In 1964, under her supervision, IMD launched India’s first ozonesonde balloon, a delicate cylinder of glass and Teflon that rose over the Deccan Plateau before bursting at an altitude of 30 km. “As the balloon climbed, ozone levels increased sharply until it burst,” recalled her colleague, C R Sreedharan. “We phoned Miss Mani at 2 a.m. She was thrilled—not by the drama, but by the data.”
That data, painfully logged and analysed, became India’s first vertical ozone profile. It later formed part of the World Meteorological Organization’s global ozone mapping effort, making Pune a critical node in what would become the planetary climate-monitoring network.
But Mani was not content with upper-atmosphere readings. She began studying ground-level ozone — what we now know as tropospheric ozone, a potent greenhouse gas formed by the reaction of hydrocarbons and nitrogen oxides.
In her mid-1960s reports, she described “a chain of reactions involving hydrocarbons and nitrogen-containing gases” — phrasing that prefigured modern climate chemistry by decades. She compared readings from Pune’s industrial air with those from the clean marine breeze of the Bay of Bengal and noted that urban pollution reduced atmospheric conductivity by nearly half.
“Closer to the coast,” she wrote, “the effect of pollution could be felt, and the values were about half of what was seen in the clean air over the centre of the Bay.”
She did not yet call it the Anthropocene — that word would not appear until the 2000s — but her graphs, equations, and field notes were its earliest Indian chronicle.
If Mani was revolutionary, she was also exacting. Her instruments were both elegant and uncompromising. European ozonesons in use at the time often produced errors because lubricants reacted chemically with the ozone. Mani’s design, built in India, eliminated this flaw by using non-reactive materials such as glass and Teflon.
“In the Indian sonde, the use of a non-reacting, non-lubricated pump eliminates this error,” she wrote in a 1972 IMD technical paper—a line of characteristic understatement that masked the ingenuity behind it.
Her laboratory reflected that ethic. Tables were spotless, instruments gleamed, and her assistants followed strict calibration rituals. “Accurate measurements are the foundation of understanding nature,” she would say.
To Mani, measurement was a moral act — not mechanical, but philosophical. “You can, but do your best,” was her motto, written in neat script on the wall of her Pune lab.
Gopinathan calls this Mani’s “spirituality of precision”—a belief that one honours nature not through poetry or prayer, but through exact observation.
By the 1970s, under Mani’s leadership, Pune had become India’s National Ozone Centre and later the Regional Ozone Centre for Asia (WMO-RA II). From here, she coordinated data flows from Kodaikanal, Thiruvananthapuram and other observatories, helping map ozone trends across the tropics.
Yet she remained deeply local in her concerns. As Pune’s population and industry grew, Mani noticed shifts in humidity, temperature, and monsoon behaviour. “The city’s skies are no longer what they were,” she told a colleague, lamenting how “urban dust and industrial vapours” interfered with radiation readings.
She was among the first Indian scientists to link urbanisation with microclimatic change — a connection that environmental researchers today take as foundational.
Her notebooks from the 1970s, cited in Gopinathan’s biography, describe the city’s “increasing nighttime warmth” and “shortened monsoon onset,” both linked to industrial aerosols. The language was scientific, yet the underlying message was moral: development itself was rewriting the atmosphere.
By the time global attention turned to ozone depletion in the 1980s, Mani had retired to Bengaluru. Yet, her early ozone data became essential baselines for later climate models.
In her later years, she remained alert to environmental questions. In a 1993 essay for Current Science, she wrote: “Although there are still many unresolved questions, and the tropics may be spared the fate of the higher latitudes, there is an urgent need to stop flooding the atmosphere with CFCs and other pollutants.”
She was never an activist, but she had the rarest form of environmental conscience — the scientist’s conviction that stewardship begins with knowledge.
Gopinathan notes that Mani’s awareness of human-induced atmospheric change predated India’s environmental movement by decades. “In her quiet way, she was already mapping the intersection of science and society that DTE reports on today,” the author said.
When Anna Mani died in 2001 in Thiruvananthapuram, there were no obituaries on prime-time television and no awards named after her. She left behind no memoir, no campaign, and no disciples clamouring for her legacy. What she left instead was an archive — instruments, logbooks, and the moral clarity that science could still be an act of truth.
Her work was, in many ways, India’s first documentation of the Anthropocene — long before climate summits and sustainability goals. Her data from Pune, Thiruvananthapuram and Kodaikanal form the earliest measurable record of how urbanisation and industrialisation began altering the subcontinent’s air.
Two decades after her death, as India faces record heatwaves and ozone alerts in its cities, her warnings echo anew. “She measured the skies,” Gopinathan writes, “not to own them, but to understand how fragile they were.”
In the cool, instrument-lined quiet of her old Pune lab — now part of the IMD’s heritage archives — one can still find the spirit of a woman who believed that the atmosphere held both science and conscience. Before the world began counting carbon and debating climate justice, Anna Mani had already done the most fundamental thing: she had measured.
And in doing so, she gave India its first clear view of the age we now inhabit — the Anthropocene.