The 'daughter of Bengal' taking on India's PM

On a sweltering afternoon, India's Prime Minister Narendra Modi is working the crowd at a campaign meeting, some 160km (99 miles) south of the eastern city of Kolkata in West Bengal state.

"You gave her an opportunity to work for 10 years. Now give us a chance," Mr Modi says. The woman in question is Mamata Banerjee, the firebrand leader of Trinamool Congress (TMC), a regional party that has been ruling the state for a decade.

Now Mr Modi, a folksy orator, slips into thickly accented Bengali, much of the amusement of many in the crowd. He launches into a broadside against Ms Banerjee, who is better known in Bengal as "didi" or elder sister, a moniker invented by her supporters.

"Didi, o Mamata didi. You say we are outsiders. But the land of Bengal doesn't regard anyone as an outsider," says Mr Modi. "Nobody is an outsider here."

Ms Banerjee has framed the challenge from Mr Modi's Hindu nationalist Bharatiya Janata Party (BJP) as one between the insiders (Bengalis) and the outsiders (the largely Hindi-speaking BJP, which runs the federal government).