On January 24, the Gujarat Pollution Control Board, gpcb, asked 15 polluting industrial units in Ankleshwar to close down. The regulatory body said the units violated environmental and pollution control guidelines. There are some major companies in the list including United Phosphorous, Cadila Pharmaceuticals, Lupin and Wockhardt.

gpcb officials said the units did not treat effluents under norms. The companies did not operate their treatment plants efficiently.

It asked 11 industrial units to stop operations immediately, but gave four big units 15 days time to upgrade the treatment facilities.

"We inspected the industrial areas of Ankleshwar and Panoli. We will inspect a few more such units and will initiate similar action if they are guilty,' said a senior officer with gpcb.

The board has also given notice to 26 other units which have not paid their user charges for gpcb's common effluent treatment plant.