Surat, India

According to The National Council of Applied Economic Research, India's premier economic research institution, the average annual household income in Surat, India’s diamond manufacturing center, was the highest in the country at Rs. 457,000 ($10,900). Industry
analysts believe Surat polishes 80 percent of the worlds diamonds by volume and employs approximately one million people (?).

Useful link:
www.ncaer.org