A textile printing company in Shangyu district of Shaoxing, Zhejiang province, was fined 20 million yuan ($3.2 million) on Monday for illegally discharging pollutants into nearby rivers.

The fine was the highest in the province for environmental pollution.

A total of 11 people involved in the case were sentenced to from six months to four years in prison.

Yan Haixing, owner of Zhejiang Huidelong Textile Printing Co, installed secret tubes in June 2012 to avoid supervision. The company secretly discharged 5,000 tons of waste during July and August of 2012, and 18,000 tons of waste from April to September of last year.

The company spent just 1 million yuan in dealing with this waste, a fraction of what it would have cost to legally dispose of the waste. Disposal of wastewater under national regulation can be as high as 2,700 yuan per ton.