The Election Commission on Tuesday told Aam Aadmi Party chief Arvind Kejriwal to provide evidence for his allegation that the Bharatiya Janata Party government in Haryana was deliberately poisoning water from the Yamuna river being supplied to Delhi.

While the poll panel did not issue a notice, it directed the former Delhi chief minister to respond with a “factual and legal matrix along with evidentiary support” by 8 pm on Wednesday to allow it to examine the matter and take appropriate action.

The Bharatiya Janata Party denied Kejriwal’s allegation, and accused him of trying to “spread fear and anarchy” among the people of Delhi ahead of Assembly elections. The Delhi Assembly polls are scheduled to take place on February 5 and the votes will be counted on February 8.

On Monday, Kejriwal shared a video on social media of Delhi Chief Minister Atishi alleging a conspiracy by the BJP to poison drinking water in Delhi. “All of us Delhiites together will fail this conspiracy of BJP,” Kejriwal said.

Atishi, in a letter to the Election Commission on Tuesday, claimed that high ammonia levels in water entering Delhi from Haryana had rendered the city’s treatment plants “almost incapable” of treating the water effectively.

She said that the chief executive officer of the Delhi Jal Board addressed a note about the matter to the Delhi chief secretary on January 27.

Referring to this allegation, the Election Commission said Kejriwal’s allegation that there was an attempt to poison Delhi’s drinking water, and equating it with nuclear and biological warfare was “extremely serious and unprecedented”.

It added that it had seen a report of the Delhi Jal Board’s report, which it said did not mention any poisoning in the Yamuna river.

“The electors tend to believe whatever is being said in public by their leaders and in that sense the statements, if not true, affect the campaign discourse, thereby vitiating the purity of elections and erode the trust of the voters,” the Election Commission said in the letter to Kejriwal.

The BJP on January 27 complained to the Election Commission against Kejriwal, saying his allegations constituted a “severe breach of several electoral and other statutes in addition to electoral ethics”. It accused the AAP chief of trying to create discord between the residents of Delhi and Haryana.

Union Environment Minister Bhupender Yadav remarked that Kejriwal’s statement reflected “the frustration of AAP's certain defeat in the Delhi elections”. He urged the Election Commission to take strict action against the former Delhi chief minister.

Congress leader Ajay Maken said on Tuesday that if Kejriwal was lying about poison being mixed in water, it amounted to treason.

“If the Haryana government is wrong, action should be taken,” he said. “If Arvind Kejriwal is spreading rumours, action should be taken against him.”