"Besides levelling unfounded allegations in these elections, BJP leaders, including PM Modi, have had no control over their tongues...like the charge that Opposition abuses them. This is most indecent and unrestrained," Mayawati said in a statement issued here in Hindi.
At the same time, she cautioned, opposition leaders too should not cross the line of decency and not give BJP an excuse to exploit public sentiment to hide its weaknesses.
Mayawati was among four leaders, including BJP's Yogi Adityanath, who were banned by EC for varying periods for violating the moral code of conduct during election campaign.
Mayawati's 48-hour ban has ended while Adityanath has one more day left before his 72-hour ban ends.
Returning to the poll campaign, she has also accused the UP chief minister of "blatantly" violating the ban imposed on him, after Adityanath tried to canvass by visiting temples.
She also accused the EC of ignoring the violations.
As the second phase of polling was under way on eight seats in UP, the BSP chief urged electors to elect a government which works "dedicatedly" to bring "achchey din".
She said the Election Commission has yet to establish it was acting independently and impartially and has not bowed its head before the central government.
Mayawati said people's confidence will be restored only when the commission acts firmly and also against the ruling party.
On the day she was slapped with a 48-hour ban on campaigning by the EC for her "provocative" communal remarks, Mayawati alleged the decision appears to have been "taken under pressure" and it will be remembered as a "black day".
(With additional information from PTI)