The Bangalore Urban district Commissioner has been asked to take action against the industries.

Arkavathy and Kumudavathy rivers are the only source of water for Thippagondana Halli reservoir (T G Halli) from where a part of Bangalore gets water.

A survey by a special committee of the forest and ecology department found these industries discharging chemical effluents in the catchment areas and also polluting the groundwater.

One of the officials of the forest, environment and ecology department said, “We have sent our recommendations and it is up to the commissioner to act at the earliest.

These industries may lose their licences and power supply may be cut off to them, to stop them from functioning immediately.” In 2003, a state government notification banned industries that discharge chemical effluents in the catchment areas of the T G Halli reservoir.

The catchment area was divided into four zones. Zone 1 includes 461 square kilometre of catchment area of the reservoir. Over-exploitation of groundwater, quarrying and stone crushing and disposal of solid and liquid waste without proper scientific processing are prohibited in this zone.

An area within two kilometre radius of T G Halli reservoir is included in zone 2 and any activity other than organic farming is prohibited without prior permission in this region.

Zone 3 is an area within one kilometre radius of the banks of Arkavathy till Hesaraghatta and an area within one kilometre radius of the banks of river Kumudavathy.

Prior permission is needed from appropriate authorities for any activity other than agriculture in this region.

Zone 4 is an area within one kilometre radius beyond zone 3.

Green industries, categorised so by the Karnataka State Pollution Control Board, are permitted here.

The special committee of the forest and ecology department found that the industries were violating zonal norms