Nearly two million population spread over eight districts in Bihar continued to reel under the impact of floods as the overall situation remained unchanged with major rivers, including Punpun, Bagmati and Kosi, in spate.
The Punpun crossed the danger mark and breached its embankment near Patna.
Engineers struggled overnight to plug the breach with sandbags, officials said.
The worst-hit districts include Muzaffarpur, Sitamarhi, Sheohar, Saharsa, Madhubani, besides East Champaran and West Champaran, they said.
Due to heavy rains during the last two days, rivers, including Kosi originating from Upper Nepal, were rising, posing a threat to the embankments, they said.
In Sitamarhi, swollen Rato river breached the embankment in a stretch of 100 feet at Srikhandi under Sursand block in the district, inundating more than 200 villages.
In Bhagalpur, incessant rains during the past two days inundated several villages and the train services in Bhagalpur-Mandarhill section have also been suspended.