Off the Ukkadam – Sundakkamuthur Road, about a km away, in the midst of banana farms lie three or four thatched roofed temporary structures.

At first sight they appear to be houses or sheds for watchmen.

But they are not. They are not even mushroom cultivation farms, as a board outside one of the sheds claims. They are yarn dyeing units.

Nearly a dozen workers, surrounded by green cover are actively dipping yarn into tanks with dyes.

A few yards away, behind pots on firewood, lay pools of dyed slush. Such pools are spread over the banana farm, as there is no proper effluent disposal system.

The effluent runs straight from the tanks into the farm. There is no treatment facility, either.

The entire operation is manual. The only machine is the water pump, which runs on diesel and not electricity.

The “illegal” units have been going for six months, complains farmer N.G. Prabhuram. “The effluent from the dyeing units reaches River Noyyal to pollute the river. It will sniff out whatever little life is left in the water. It will also affect agriculture lands that are dependent on the water.”

His farm is south of the River and dependent on its waters.

The functioning of the make-shift units came to light when farmer P. Suresh and his friends went bird-watching along River Noyyal.

“The mushroom farm board drew me closer to the thatched roofed structures. But I was shocked to find dyeing units without effluent treatment facility.”

The operation is so low-key that it is difficult to observer. Dyed yarns are transported on two-wheelers. No big vehicle is used.

The units are also close to the Big Tank's surplus weir as well. To be precise, they are south-west of the Tank, sandwiched between the weir and River.

There are around 100 acres agriculture lands North of the River and another 50 in the South, all of which will get affected if the units continue to do what they do, he adds.

The workers refuse to identify themselves. They also claim to not know the owners name or phone number.

“We do not have the numbers,” they told The Hindu.

Sources in the Tamil Nadu Pollution Control Board say they are seized of the issue related to the dyeing units. Thanks to farmers, they got wind of the activities there.

Conceding that it is difficult for the Board to identify such make-shift units, the sources say they depend on tip-off from public. In the last six months, the Board has sealed six such units in various parts of the district – from Anaimalai to Singanallur to Podanur.

The Board is waiting for approval from its headquarters in Chennai to seal the units. It is expected anytime, the sources add.