A look at some of the interesting constituencies and the evolving battles:
Varanasi (Uttar Pradesh): Varanasi district, home to Hindu's ancient city, would witness the most interesting electoral battle - between BJP's prime ministerial candidate Narendra Modi and the rest.
Aam Admi Party (AAP) chief Arvind Kejriwal has said he will fight against Modi, but has yet to confirm it.
The final announcement will be made on March 25. While the Congress has yet to name its candidate, the name of Modi baiter Digvijaya Singh has been doing the rounds.
Mukhtar Ansari, of the Quami Ekta Dal, is expected to give Modi a strong fight as the constituency has a significant Muslim population.