Calcutta, Dec. 12: The green bench of Calcutta High Court today directed the state pollution control board to serve notices to 35 civic bodies on both sides of the Ganga asking them to introduce effluent treatment plants.

The bench of chief justice A.K. Mathur and justice A.K. Bannerjee refused to accept a pollution board report on the Ganga Action Plan that said water samples from 35 outlets leading to the Ganga have shown a decrease of bio-chemic oxygen demand (BOD) by up to 25 per cent.

BOD is a test to measure the purity of water. In pure water, its count should be less than 600. In 1991, Ganga water in the state had a BOD of more than 2,000. The pollution board report said the figure now stands at 1,117.

Environment activist Subhas Dutta told the court that there are 250 mouths draining water into the river in the state. “The PCB (pollution board) has taken samples from only 35 points. The result does not prove that the river water has been purified,” he said.

Mathur told the pollution board lawyer that 17 years have passed since the Ganga Action Plan was launched and crores spent but nothing much has been done to clean the Ganga in Bengal. The bench asked the board to furnish a fresh report on the bio-chemic oxygen demand and be more active in overseeing the river clean-up.

The board’s report also said untreated effluents drained by municipalities adjacent to the Ganga were contaminating 45 per cent of the river water.

The court directed the board to get in touch with the municipalities within three months and ask them to set up the effluent treatment plants.

Environment activist M.C. Mehta had initiated the case in the Supreme Court. The apex court ruled that the Bengal part of Ganga pollution would be heard by the high court.

Appearing before the high court, Mehta had alleged that the Ganga is most polluted in Bengal. He alleged that untreated effluents from industries on the banks is polluting the river. Dutta represented Mehta today.

The court asked the pollution board to serve notices to the industries to introduce effluent treatment plants. A recent board survey, however, said almost all the factories have installed the effluent treatment plants.