Four days after a large cloud of froth accumulated in one corner of Hyderabad's RK Puram Lake, officials from the Pollution Control Board (PCB) took samples of the water on Thursday.
PCB officials visited the spot on Thursday evening, and collected water samples near the froth, and from other outlets, for testing.
"It could be anything. We can only say what it is conclusively, after the lab results come back," N Raveendhar, a senior scientist from the PCB, who was present at the spot told TNM.
Earlier in the week, several locals rushed to the spot, after they saw the lake spewing out froth and foam, following a bout of rainfall.
Curious onlookers took pictures and videos, and also notified the authorities about the incident.
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.
The PCB officials were accompanied by noted environmentalist and lake protection expert BV Subba Rao.
"We must first identify the basics. Where does the lake get water from, and where does the water go? Then, we must identify any potential spots from where the pollution is seeping in," he told TNM.
Rao also said that the nutrient content of the lake seemed to have a high amount of nitrates and phosphates.
"It is possible to clean up the lake and reverse it, with a few simple steps. It just requires coordination among the local residents, as there is no point in waiting for the government to act," he added.
Activists suspect that the froth is definitely chemical in nature, as it emitted a strong, pungent smell.
However, the froth continues to build up, as both locals and officials do not know how to get rid of the thick layer of foam that has accumulated on the water.
Meanwhile, the Greater Hyderabad Municipal Corporation had said that it may establish a sewerage treatment plant (STP), with an official saying, â€œEstablishing an STP can address the problem, but we will take up the issue with the PCB."
However, Subba Rao contended that the STP would only offer temporary respite, and was not a permanent solution.
Rao also advised local residents and PCB officials to take steps to ensure that the froth stays low, and doesn't get spewed out onto the road, or nearby houses.
"We can do this, by taking steps to control the height and speed of the water, near the outlet," he said.
This is also not the first such incident reported in the city this month.
On June 8, Dharani Nagar witnessed froth, several feet high, along the Kukatpally nala.
However, the PCB has since claimed that it was an 'episodal pollution' and said that the foam was caused by 'detergents and phosphates'.