कोसी नदी का जलग्रहण क्षेत्र कितने वर्ग किलोमीटर में फैला है ? - The catchment area of Kosi river is spread over how many square kilometers? - Kosi Nadi Ka Jalagrahann Shetra Kitne Warg Kilometer Me Faila Hai ? Bihar Gk in hindi, Canals and Irrigation 40 , 000 Warg KM question answers in hindi pdf 36 , 000 Warg KM questions in hindi, Know About 30 , 000 Warg KM Bihar Gk online test Bihar Gk notes in hindi quiz book 10 , 000 Warg KM