Residents and elected representatives are up in arms against BMC's apathy after around hundred odd fishes have been found floating dead in the polluted Sion pond during the past two days. The pond had last witnessed a mass fish deaths in 2012 where almost all the fishes in it died.

Former principal scientist at Central Marine Fisheries Research Institute (CMFRI), Dr Vinay Deshmukh said that one of the most common reasons for fishes dying in water bodies specially ponds and lakes is due the lack of oxygen. "I have not visited the spot but going by the photographs and information , it clearly seems that the deaths are due to the increase in the organic pollution, which reduces the dissolved oxygen levels. Most of the fishes that are dead are species of cat fish, which are already sensitive," he said stating that the pond water must be getting contaminated with sewage or other pollutants.

Meanwhile BJP councillor of ward 172 Rajshri Shirwadkar expressed concerns over the death of fishes. She said that people immersed floral offerings as well as coconuts in the pond and despite repeated reminders BMC did scant action to save this historic pond. "It was first on Sunday morning that around 40 odd fishes were found dead and floating in the water and similarly around 50 were found on Monday and most of these fishes are fully grown and over 10 to 20 kg," Shirwadkar said adding that the last clean up of the pond was done in around 2011. It has never been cleaned since then despite regular idol immersions happening in the pond.

Deshmukh informed that a pristine fresh water body has around 6ml of oxygen per litre of water and the oxygen level can drop to less than 1ml of oxygen per litre of water in very polluted water. "Due to the pollution the dissolved oxygen reduced and it is lowest during early morning and hence most of the fishes are found dead during early morning period and this phenomenon is quite common during winters," he said adding that some one needs to do a detailed study of the pond its water quality and not simply test the BOD, which might not result in proper results.

Dr MJ Pravin Bhatt who is a priest in the nearby temple was pained by the death of the fishes. He bought an aeration machine to increase the oxygen in the pond. "Its a painful sight to watch these fishes that are dying due to lack of oxygen, hence I decided to buy this machine and installed it," he said.

Assistant Municipal Commissioner of F-North ward, Keshav Ubale said, "I have received a complaint from citizens that few fishes have died in the lake. Following residents complaints the pond water will be tested. We do not have any contractor for the maintenance of the lake, it is a natural body and has aquatic animals like fishes and tortoises."