India`s governing Bharatiya Janata Party has conceded defeat in the key state election in Bihar, in what is being seen as a major blow for the prime minister, Narendra Modi, reports aljazeera."Had a telephone conversation with Shri @NitishKumar & congratulated him on the victory," Modi said on Twitter of Kumar.Nitish Kumar, the incoming chief minister, said on Twitter on Sunday that Modi had called him and congratulated him on his party`s victory in Bihar, one of India`s largest and poorest states.Election Commission results showed Modi`s BJP leading in only 52 seats in the 243-seat state assembly compared to 158 for Kumar`s coalition of regional parties, as vote counting continues.Modi had mounted a no holds barred campaign in Bihar, addressing about 30 rallies and promising voters billions of rupees for development in a state with some of India`s highest malnutrition and illiteracy levels.The election for the state assembly was seen as a critical test of Modi`s popularity after he swept to power in national polls in May 2014, promising ambitious reforms to revive the faltering economy.