The Bharatiya Janata Party's repartee came during its mega rally here led by national working President J.P. Nadda in support of the new citizenship law.
Amidst incessant slogan shouting, many of them targeted Banerjee, as one of the youth suddenly shouted, "Ei Didi, chi chi," while others followed in unison "chi chi, chi chi". Banerjee is often addressed as Didi, meaning elder sister in Bengali.
Chi chi is a Bengali expression used to shame somebody for doing something grossly wrong and condemnable.
At the BJP rally, the slogan immediately found a lot of takers and continued for some time accompanied by rhythmic clapping.
A little later, however, the version changed, though Banerjee continued to be at the receiving end.
"Didi tumi ca, ca," shouted one youth, and immediately the others roared back "ca ca ca ca".
It was BJP's way of getting back at Banerjee for having mocked the new citizenship law.
On Friday, a 12-minute video clip of Banerjee chanting the slogan at Park Circus Maidan in south Kolkata to protest against the Citizenship (Amendment) Act at a public rally went viral.
One user posted the clip in which Banerjee says "CAA CAA Chi Chi" and the audience repeats it after her. The user wrote: "I'm just leaving this here, in case anyone needs to laugh uncontrollably. #CaaCaaChhiChhi."
It got 163.9K views, 1.5K retweets and 4.2K likes.
( With inputs from IANS )