The biggest reason is that about 35 million female voters of Bengal can play a big role
Sometime in 1973, a woman approached Prime Minister Indira Gandhi with her husband. She wanted to contest the next assembly election. Her confidence impressed the then prime minister and, a few weeks later, the Congress gave her a ticket for an assembly constituency in a backward district of Uttar Pradesh. At the time, she had no idea what difficulties she would have to face to accomplish her goal.