While we are getting cynical about Ulsoor Lake turning into a death bed for fishes and claiming it to be something that occurs every year, there are people who explain this should not essentially be the natural course of things.
"Fish deaths happen once a year, during the first showers. That is natural. But I am assuming that Monday's incident is more of a fish-kill," says Brigadier Devaiah, who has been working on lake development and cleansing in south India.
Prof. Zutshi Bale, who teaches Zoology at Bangalore University, echoes the same opinion as Devaiah. She says that the reason for sudden mass fish deaths is illegal waste dumping from industries which have failed to put in place mandatory waste disposal mechanisms. Often, it is dumped in the dead of the night to avoid detection.
"It is an open secret that effluents and sewage waste is pumped into the lakes. But the moment cakes of old effluents are pumped into the lake, large number of fishes die. These effluent-cakes are 5-6 months old, highly poisonous, and settle on the lake bed. Overnight, they deplete the oxygen available and leave the organisms gasping for breath," said Zutshi, who has been studying development of water bodies in Bengaluru for over 10 years.
What happened to all the clean-up plans or were there any?
Ulsoor lake is owned by the Bruhat Bengaluru Mahanagara Palike but maintenance was handed over to Prestige Group through an MoU in May 2015.
"BBMP cannot take up any project that costs over Rs 5 crore. Though it was handed over to them, the MoU never mentioned cleaning of the lake. They have been working on the beautification around the lake ignoring the fact that work needs to be done in the lake," Devaiah said.
According to a Deccan Herald report, the Karnataka State Pollution Control Board, BBMP, BWSSB and Lake development authority and come up with Rs 9.31 crore plan in 2013 to rejuvenate the lake. Randhawa Broson Enterprises, which was to take up the aeration of the lake, says that the plan never took off.
Sukhwinder Randhawa, founder of Randhawa Broson Enterprises says that the only way to revive a lake in the city is to aerate it, which is pump in oxygen from under. Randhawa says that there is no political will to develop the lakes.
Randhawa Borson Enterprises in 2007 cleaned up the Nainital Lake, which saw a drop in the number of tourists during the years before the clean-up. Now they are also going to be working on reviving the Ootacamund Lake.
“I have given too many presentations to the ministers and the officials many times in the last few years. They just don’t seem to be do anything nor do they get back to us,” he said.
"Since the city is pumping in so many effluents into the lake all the oxygen in the lake is used up to break the matter. So naturally the lake has turned anaerobic," Randhawa said.
However, Dr. Jayaprakash Alva, a member of the Karnataka State Pollution Control Board said that the lake has been cleaned every year. But, only if the officials personally test the water on Tuesday, they would be able to comment on the reason behind the fish-deaths.
According to Davaiah, the KSPCB has constantly been classifying Ulsoor Lake under Class-D (polluted). "Sometimes it even falls under Class-E which means dead lake," said Devaiah, who has been studying lakes cleaning in south India for over five years.
While there is an option to desilt the lake, there is always a fear of puncturing the lakebed. If the lake bed is punctured then the lake would never be able to hold water, claims Devaiah.
In February 1998, a major project to desilt Ulsoor lake took place. The water was completely drained out and the silt was removed.
However, the lake’s condition deteriorated in five years, necessitating another cleaning up project.
“There are other options like spraying microbes, which was recommended for Bellandur Lake. But those too need oxygen. Where is the oxygen?” he asks.
Lack of live water bodies is also affecting the larger ecosystem. Mosquito problem is one of the results.
"If you see Bengaluru has very few dragonflies over the last decade. This is because their major part of their life-cycle involves water. And since there is no oxygen supply in the lake the larvae die. Dragonflies survive on mosquito larvae. Thus, you have an increase in mosquitoes in Bengaluru," said Zutshi.