Activist Medha Patkar was forcefully taken to New Delhi's All India Institute of Medical Sciences on Wednesday night, when her health became critical after being on a hunger strike for eight days.

Patkar and her Narmada Bachao Andolan colleagues are protesting the Narmada Control Authority's green signal to raising the height of the Sardar Sarovar Dam from 110.64 metres to 121.92 m.

If you are wondering what the fuss is about, here is a quick guide to a mass movement that includes in it many unanswered questions about India's road to development.

Why all the controversy over raising the height of a dam?

The issue is not just about one dam, though the trigger is.

The Government of India plans to build 30 large, 135 medium and 3,000 small dams on the Narmada River and its tributaries.

The government says the dams will provide much-needed water and electricity to drought-prone areas in Gujarat, Maharashtra and Madhya Pradesh.

The opponents -- namely the Narmada Bachao Andolan, led by Patkar -- say the dams will displace a large number of poor and underprivileged people whose lives depend on the river.

The NBA also says the concept of big-dam mode of development is fundamentally flawed.

The agitators agree that water and electricity shortage in parts of Gujarat, Maharashtra and Madhya Pradesh are real. But they say there are alternate ways to addressing those problems.

They argue that the millions of people will lose their livelihood, their land, their identity -- thanks to the dams.

But the immediate issue is the Sardar Sarovar Project. Right?

Yes. The immediate issue is the SSP, which is the biggest mega-dam in the Narmada development plan.

The NBA says the raising the height of the dam is illegal, as the Supreme Court had ruled that the height cannot be increased without rehabilitating every affected family.

It is to protest this decision to raise the SSP dam's height that Patkar and her colleagues are agitating in New Delhi.

Just who is Medha Patkar and how did she get involved in this movement?

Medha Patkar is widely held as one of India's most-respected activists. She was born on December 1, 1954 in Mumbai. She comes from a family of mass movement leaders -- her father was a freedom fighter and her mother worked in a women's organisation.

Patkar did her masters in social service from the prestigious Tata Institute of Social Sciences in Mumbai. She wrote her initial research papers on economic development and its impact on traditional societies.

As a student, she had close interactions with the people in the tribal areas of Gujarat and Maharashtra, which changed her life, and theirs.

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Her struggle against the oppression of poor tribals began with the demand of information about the development plans of the Naramada Valley. How can the government make plans to bulldoze a culture, a way of life steeped in history without consulting or rehabilitating the people who would be affected, she asked.

The question became the movement.

Wasn't the World Bank involved in the Sardar Sarovar Project?

Yes, it was to give $450 million for the project. Thanks to Patkar's and the NBA's untiring peaceful campaign, the World Bank was forced to constitute an independent review committee for the project in 1991.

The Morse Commission -- headed by former United Nations Development Programme chief Bradley Morse -- said the environmental and human concerns about the project were genuine.

The Commission's report said, 'the Sardar Sarovar Projects as they stand are flawed, that resettlement and rehabilitation of all those displaced by the Projects is not possible under prevailing circumstances, and that the environmental impacts of the Projects have not been properly considered or adequately addressed.'

The World Bank washed its hands of the project through what is believed to be a face-saving agreement: The Government of India asked it to pull out.

But the Supreme Court cleared the project, right?

Yes. On October 18, 2000, the Supreme Court of India allowed construction on the dam up to a height of 90 metres. The judgment also authorised construction up to the originally planned height of 138 metres in five-metre increments subject to the Relief and Rehabilitation Subgroup of the Narmada Control Authority's approval.

Booker Prize winning author-turned activist Arundhati Roy courted arrest for contempt of court because of her outspoken criticism of the 2-1 majority judgment.

So it's Medha Patkar versus development and technology?

The lady herself would disagree.

'I am not anti-technology, I am all for it: beautiful, harmonious, equitable, sustainable, egalitarian, non-destructive technology,' she said in a recent interview.

'Not this gigantic technology which is apocalyptic, destroying thousands of homes, hearts, habitats, ecology, geography, history, and finally, benefiting so few, and at such great cost. This is mindless and this is violence.'