Calcutta, Jan. 31 :    Calcutta, Jan. 31:  Calcutta is on the brink of a water crisis. Supply has been cut down drastically by about 10 million gallons a day as micro-organisms have choked the filter-beds at the Palta waterworks, said member, mayor-in-council (water supply), Sobhan Chatterjee. The situation has been compounded with the 20-million-gallon, French-built, water treatment plant at Palta developing snags. It is unable to supply more than 10 million gallons, which is about half its normal capacity. Moreover, the quantity of filtered water produced by the Palta plant every day is being supplied to Salt Lake, taking the total deficit in the city to 30 million gallons. The water supply network of the Calcutta Municipal Corporation produces 180 million gallons of filtered water a day. The CMC started supplying filtered water to Salt Lake in 1998. 'We came to know about the problem of micro-organisms only a couple of days ago. It cropped up when water samples were examined under electron microscopes in our laboratory at Palta,' said Chatterjee. A senior engineer in the Palta waterworks said there are 88 filter-beds in Palta, producing 180 million gallons of water a day. 'We are trying to combat the micro-organisms by pouring chlorine and copper sulphate solution in the unfiltered Hooghly water and sedimentation tanks before sending them to the filter-beds,' he said. Chatterjee said this massive multiplication of micro-organisms in the river water often occurred during the pre-monsoon months, but this time, it has occurred during winter, when the water level in the Hooghly recedes. 'It has taken us by surprise,' he added. 'Records say the problem caused by micro-organisms generally last for 15 to 20 days. The situation would have been better if the civic body had not been burdened with the load of supplying 10 million gallons of filtered water to Salt Lake every day,' said Chatterjee. But engineers in the water supply department said the snag at the treatment plant was of a 'highly technical' nature and could not be repaired immediately. 'This plant is unfit for filtering the Hooghly water, which is highly turbid. Even if it is repaired, it will develop the same snags again,' an engineer said. Consequently, there has been a fall in the water pressure in the city. The supply to household taps is delayed and stops before the slotted hours.