Toxic foam from the polluted Varthur lake in Bengaluru spilled onto the roads, sparking health concerns among residents, who have repeatedly urged the authorities to clean the water body to no avail. The froth has been a perennial problem in the polluted lake due to high content of ammonia and phosphate and low oxygen levels, a result of inflow of sewage and harmful effluents. The residents said the thick, snow-like froth served as a breeding ground for diseases and caused an unbearable stench in the area. The foam also poses problems for motorists as it spreads all over the roads, leading to long traffic Jams. Residents said that repeated pleas for cleaning the lake had fallen on deaf ears. During rainfall, the problem compounds leading to a rise in the levels of froth in the lake.