Heavy rain lashing Hyderabad for two days has resulted in froth surfacing once again, at the RK Puram lake in Secunderabad.
The froth was seen bubbling and increasing with each minute on Tuesday, as rain continued to pour, increasing the speed of the water exiting the lake.
The froth continued floating on the surface of the water, as it left the lake, into a nala, and managed to choke a large sewage pipe.
"It started with a little bit last night, and has increased a lot today (Tuesday) morning. If the rain doesn't stop, it will soon spill out on to the roads," a local at the spot, observed.
The pungent smell that had decreased over the past few days also increased again, he added.
The frothing was first reported in June, but locals had managed to decrease the quantity of the foam that accumulated at one end of the lake.
Speaking to TNM, Sainiknagar Association President, Murali Chemuturi said, "The froth has actually not decreased. We managed to regulate the increase and decrease of the foam, depending on the inflow of effluents in the lake."
"The quantity of froth is directly proportional to the number of effluents being discharged into the lake," he added.
However, he assured that the froth would not spill out on the roads if it continued to rain.
"When it rains, it (froth) gets diluted. Because of dilution, the froth travels with the flowing water. However, it will not come out on the roads, and will enter the underground drain," he said.
He also added that there was no temporary solution as of now, the permanent solution being the redirecting of sewage lines, into another water body.
Last week, a preliminary investigation by the Pollution Control Board (PCB) showed that the lake may have frothed, due to a mixture of sewage and alleged dumping of animal waste.
"Our preliminary analysis revealed that there is organic matter in the samples of the lake. We suspect that someone has been dumping pig waste in the water. There is also a cattle farm nearby, which may be dumping the organic matter. We are bringing that to the notice to the government," N Raveendher, a senior scientist from the PCB, had told TNM earlier.
Detergent levels, which should be 1 mg, were roughly between 2 mg to 3 mg, while phosphate levels were almost ten times more than the ideal limit.
The extremely high amount of nutrients in the lake, led to its eutrophication, and a dense growth of water hyacinth, officials added.
The lake is a part of the Alwal catchment area and is fed by water from several smaller bodies in the area. From here, the water travels to the Safilguda Lake, also known as the 'mini tank bund', before travelling to Banda Cheruvu (lake) and finally ending up in the Musi River.
Hyderabad received 41.8 mm rain till 8:30 pm on Monday, which is the highest on a single day this monsoon season.
Many areas near the lake, like Neredmet, Safilguda, and Anandbagh also witnessed waterlogged streets and inundated roads.
The Indian Meteorological Department (IMD) has issued a two-day warning for the state, for Tuesday and Wednesday.
"Heavy to very heavy rain very likely to occur at isolated places in all the districts of Telangana," the warning read.
It has attributed the extra rain to "a well marked low pressure area over northwest Bay of Bengal with an associated upper air cyclonic circulation extending up to 7.6 km above mean sea level."
It also said that the low-pressure area could intensify into a depression during the next 24 hours.