In the southern Indian city of Madurai, jigarthanda is a popular, cooling street drink.

BBC: What should I drink in your country?

Most people who visit the center are too poor to pay for the trek to Madurai.

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One such site is at Alanganallur, a village 20 miles north of Madurai.

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Diagnosed with brown cataracts in both eyes and advised to have surgery, Pillai will be taken to Madurai at Aravind's cost and treated for free.

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Twenty cases of female infanticide, in which the mothers were punished, have been documented by a Madurai-based non-governmental organisation, the Society for Integrated Rural Development.

BBC: India rights campaign for infanticide mothers