The Congress and the Left have joined hands in Bengal to challenge the Mamata Banerjee government, which is seeking a third straight term in next year's assembly elections. Senior state leader Adhir Ranjan Chowdhury announced the Central leadership's approval to the state unit's request this afternoon. "Today the Congress high command has formally approved the electoral alliance with the Left parties in the impending election of West Bengal," Mr Chowdhury posted on Twitter.