Even as residents in Hyderabad's Dharani Nagar got temporary respite from a frothing nala neaby, the RK Puram lake in Secunderabad began spewing foam on Sunday. 

The lake which has been frothing for close to two months now, was spewing foam onto the adjoining road, thereby threatening motorists and commuters on the stretch.

The frothing at the RK Puram lake was first reported in June, following which officials from the Pollution Control Board (PCB) visited the lake and collected water samples.

“From our initial investigation, all we could ascertain is that there is a lot of organic waste inside the water. Its reaction with the water was further aggravated in the recent rains, which catalysed the entire process. That is why there is a lot of foam on the lake," BV Subba Rao, an expert on urban lakes and their biology, told the Times of India.

“The cause of foam in the canal could be the presence of filamentous bacteria. Since the movement of water inside the canal is considerably turbulent, it must be aggravating the bacteria, resulting in foam," N Raveendhar, a senior scientist with PCB told TOI.

Preliminary tests also showed that the lake may have frothed, due to a mixture of sewage and alleged dumping of animal waste.

This frothing comes weeks after multiple raids on many piggery units in RK Puram, which resulted in hefty fines and closure notices.

The officials of the Greater Hyderabad Municipal Corporation (GHMC) who visited the spot, said that several piggeries in the area were dumping animal waste into the lake. 

According to locals, there are several illegal piggeries in the area that process pork and animal fat and continue to pollute the lake.