Kolkata, March 7 -- PM Narendra Modi sharpened his attack against CM Mamata Banerjee ahead of the West Bengal Assembly polls and asked people of the state to vote for his Bharatiya Janata Party which will help in attaining the dream of building 'Sonar Bangla'.

Addressing a mega rally at iconic Brigade Parade ground here, he said, "Today, I have come here to assure you of Bengal's development, to increase investment here, to protect Bengal's culture and to bring change."

Modi said, "We promise to bring 'Asol Poriborton' in Bengal."

He said, "Ashol Poriborton means Bengal, where trade and business flourished, where maximum investment came. Ashol Poriborton means Bengal, which has the modern infrastructure of the 21st century."

Modi, who h...