NEW DELHI, Jan. 20 (Xinhua) -- Indian army Saturday said fire that broke out in Bellandur lake in southern Indian city of Bengaluru has been brought under control.

"There have been many instances of fire in the past in the lake and it's not the first time that it has happened," Lt. Gen. Vipan Gupta, a senior army officer told media. "We are trying to find out the exact reason behind the fire."

The massive fire broke in the lake Friday afternoon, emitting off thick clouds of smoke that enveloped the area.

Apart from firefighters authorities rushed in army personnel to prevent the fire from spreading in adjacent areas.

The fire started at several spots in the lakeside -- filled with sewage, chemical effluents and growth of water hyacinth -- and spread towards the army area.

Around 5,000 troops battled for hours together to contain the raging fire in the lake and continued the operation throughout night to contain the situation.

"At any given point about 800 people were on the spot, while the remaining were preparing so that they could get into action when the team on the spot returned for reinforcement," Gupta said.

Last year, several incidents of fire in the lake were also reported.

The lake is heavily polluted as untreated sewage and pollutants get discharged in it. Experts say the polluted water emanate an obnoxious stench round the clock as sustained inflow of pollutants have increased beyond the lake's assimilative capacity and over the years has led to nutrient enrichment and profuse growth of macrophytes and algae in it.

There have been instances in the past when white toxic spume rises from the lake and floats in the air, thereby obstructing the commuting movements of pedestrians and motorcyclists.