The opposition has said the incidents expose the government's "corruption".
The record-breaking collapse of 10 bridges in Bihar in 15 days, less than a month into the monsoon season, has focused the spotlight on the quality of construction and the materials used, but the real cause may lie elsewhere, officials have told NDTV.
As part of the preparations for the monsoon, contracts were issued for the dredging and desilting of stretches of rivers in the state and the unscientific manner in which this was done has led to the collapse of these bridges, indicating lapses on the part of the contractors and also the administration.
While desilting the rivers, an official said, mud and silt were also removed from around the pillars on which the bridges stood, leaving them without any kind of base. Dredging, which involves removing mud, rocks and other material from the bottom of the river, was also done to increase the flow of water, but the effect on the embankments wasn't taken into account.
Most of the bridges, the official said, see water flowing under them with any kind of force only during the monsoon and the heavy rains in Bihar exposed these weaknesses. In some cases, the pillars collapsed because of a lack of support. In others, the rivers, flowing faster because of the dredging, eroded the embankments, depriving the tops of the bridges of support.
Chaitanya Prasad, Additional Chief Secretary of the Water Resources Department, said, "The accident happened due to removal of soil. We will take action. The government is coming up with a comprehensive policy on the maintenance of bridges."
The ten bridges that have collapsed in the past fortnight were in Siwan, Saran, Madhubani, Araria, East Champaran and Kishanganj districts. The opposition has attacked the government and found unlikely support from a senior leader in the BJP.
RJD leader and Leader of the Opposition in the Bihar Assembly, Tejashwi Yadav, said, "Both Prime Minister Narendra Modi and Chief Minister Nitish Kumar are silent over these incidents in Bihar. What happened to the claims of good governance and corruption-free government? These incidents show how corruption is rampant in every department of the state government."
Dr Nikhil Anand, a BJP leader who now serves as the party's national general secretary, has said he is "afraid" of crossing any bridge in the state.
"I am afraid of crossing through any flyover or bridge in Bihar. Surprised that in last 10 days half a dozen bridges have collapsed. A serious probe & auditing is needed. The responsibility be fixed on the construction company, blacklist them. The engineers must be booked," he said in a post on X.
Deputy Chief Minister Samrat Chaudhary said Chief Minister Nitish Kumar has ordered a survey of all old bridges in the state and an investigation is being conducted into the collapses.