"What happens in one state doesn't affect the other. In Bihar, caste politics matter while in West Bengal political equations matter. The politics of Bihar is very different from the politics of West Bengal," BJP state president Rahul Sinha told reporters here.
He said the by-elections would be fought on state level issues.
"The Congress and the BJP has an unannounced tie-up now. In the 2016 Assembly polls, they will announce their tie-up," Sinha said.
For the September 13 by-elections, BJP's Ritesh Tiwari today filed his nomination from the Chowringhee Assembly seat while party leader Samik Bhattacharya would contest from the Basirhat South Assembly constituency.