With the Tatas rolling out the Nano from Gujarat, the Communist Party of India-Marxist said on Monday the Congress will have to explain its 'unholy' alliance with Trinamool Congress which 'orchestrated' the ouster of the project from West Bengal.

"If Nano has gone out of West Bengal and is rolling out from Gujarat on Monday, the Opposition in Bengal, the unholy alliance of Trinamool Congress and Congress is responsible," CPI-M Politburo member Brinda Karat told reporters in New Delhi.

She said her party was seeking votes on the plank of alternative development policies, and added, "Nano has already been an issue in Bengal. Congress should answer as to how it is in league with those parties which said they will not allow development of Bengal and have orchestrated the ouster of the Nano project."

She said the issue of the Nano project going out of West Bengal would be discussed during the election campaign, particularly in the state, along with a number of national issues like price rise and independent foreign policy.