Surat is the centre of India’s diamond trade with more than 800,000 people employed in 4,000 factories dedicated to cutting and polishing.
The country's estimated 500,000 cutters and polishers are paid per carat - around $US12 ($AU18).
With a global decline in diamond demand, these factories have been forced to cut hours and wages and Bhavesh Tank of the Diamond Worker Union said the workers are hardest hit.
"This year, the summer vacation was extended up to 15 days in a few units which is not usual," Tank told Times of India.
"But the market conditions did not improve. So, to further reduce production, the medium and small units are working five days a week and working hours have been reduced from 11 hours to six or seven hours."
In June, the Gem and Jewellery Export Promotion Council reported a year-on-year decline of 31.5 per cent in India's gross exports of polished diamonds.
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