Six men responsible for an illegal chemical discharge that led to water supplies being cut off to 30,000 residents in suburban Shanghai received jail sentences ranging from two to five years in a Shanghai court on Wednesday.

It was the ninth judgment of an environmental pollution case in the municipality since 2010, according to Shanghai High People's Court.

"Three cases of environmental pollution, involving six defendants, were adjudicated from 2010 to 2012, and the number has risen to six cases involving 15 defendants so far this year," said Zou Bihua, vice-president of the court.