A senior DJB official on Sunday bathed in water taken from a stretch of the Yamuna where the utility sprayed a chemical to dissipate foam in the river.
The spraying of the defoamer ahead of Chhath Puja had kicked off a political slugfest with the Bharatiya Janata Party (BJP) and Congress alleging that the government used a "poisonous" chemical to remove froth.
Sanjay Sharma, the Director of Treatment Quality Control, DJB, told PTI he bathed in the water to prove that it was not harmful.
"I have been saying it from day one (chemical is not poisonous). In fact, it has improved dissolved oxygen levels in the river water and other parametres such as biological oxygen demand and total suspended solids," he said.
A video on Friday showed the BJP's West Delhi MP Parvesh Sahib Singh Verma asking Sharma, who was supervising the spraying of deformer, if the anti-frothing chemical be poured on him.
"Show me if you can take a dip in the Yamuna. You are spraying a poisonous chemical which will kill people," Verma can be seen telling Sharma in the video.
Another video on Sunday showed Sharma collecting water from the river and taking bath on the banks.
Sharma had on Friday filed a police complaint against Verma and BJP leader Tajinder Singh Bagga for allegedly "intimidating" him and "obstructing discharge of official duty".
According to Sharma's complaint, Verma used "very foul language and misbehaved with me. He is also spreading the false propaganda that I along with officers of the DJB are poisoning the water of the Yamuna river".
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The spray of the anti-foaming substance is duly approved by the DJB and has also been recommended by the National Mission on Clean Ganga under the Union Ministry of Jal Shakti, he had said.
According to officials, the primary reason behind the formation of the toxic foam, an annual affair during this time of the year, is high phosphate content in the wastewater.
Detergents used in dyeing industries, dhobi ghats and households are the major source of phosphates, they said.
Wastewater from authorised colonies and settlements containing high phosphate content reach the river through untapped drains.
When water falls from a height at a barrage, the turbulence agitates the phosphoric compounds in the river which leads to the formation of froth.
The 22-kilometre stretch of the river between Wazirabad and Okhla, which is less than 2 per cent of its length of 1,370 kilometres from Yamunotri to Allahabad, accounts for around 80 per cent of the pollution load in the river.