Preliminary results and media projections at the climax of the marathon six-week election showed the Bharatiya Janata Party (BJP) and its hardline leader Narendra Modi on track for the first parliamentary majority by a single party in 30 years.
Modi, the 63-year-old son of a low-caste tea seller tainted by anti-Muslim violence in his home state of Gujarat in 2002, wrote on Twitter that "India has won.
Good days are coming."
The stunning results exceeded all forecasts. Firecrackers exploded at BJP offices around the country and sweets were handed out in celebrations that began only a few hours after the first figures filtered out.
"This is the beginning of change, a people's revolution and the start of a new era," senior BJP leader Prakash Javadekar told AFP at party headquarters in New Delhi.
Media projections showed the BJP winning more than the 272 seats required for a majority on its own in the 543-seat parliament, with victories by its allies taking it easily in excess of 300.