Over 50,000 tonnes of silt from the underground sewers find their way to homes, offices and shops in the form of dust every year, thanks to the lack of coordination between two departments of the Calcutta Municipal Corporation (CMC).

Annoyed at the state of affairs, municipal commissioner Alapan Bandyopadhyay has asked the chief engineers of the conservancy and drainage departments to come up with a scheme to tackle the problem.

?I don?t want silt scooped out from the underground sewers and heaped on the sides of the roads,? the municipal commissioner told the chief engineers.

The conservancy department blamed the drainage department for not removing the silt immediately after it is dredged from the sewers.

The engineers in the drainage and sewerage department, on the other hand, said that if the wet silt is carried away in trucks, the dripping water will dirty the roads.

Therefore, the silt is first dumped on the sides of the roads, and removed only after it dries, they maintained.

A senior conservancy department official said hardly 50 per cent of the dredged silt is actually removed by the civic conservancy and the drainage departments.

The rest of the silt is smeared and subsequently spread on the road surface by the wheels of passing vehicles.

Once dry, the silt turns to dust and is blown by the wind into homes and shops.

Chief engineer (drainage and sewerage) Swapan Datta Gupta stated that about 60 tonnes of silt from the underground sewers are removed daily by the drainage department.

He, too, admitted that silt scooped out of the gully pits is kept beside the road before being taken to vats in handcarts.

The CMC drainage department is responsible for dredging silt from the 4,500-km-long drainage and sewerage network in the city. About 150,000 lakh tonnes of silt are scooped out in a year.

?We can remove the silt if the drainage department informs us of the spots where they have dumped it, immediately after carrying out the dredging,? said chief engineer (conservancy) Arun Sarkar.

The problem in carrying wet silt in trucks can be tackled easily by using plastic sheets, he added.