PM Modi to lay foundation stone of India’s longest bridge in Assam Guwahati, Feb 17 (UNI) Prime Minister Narendra Modi will lay the foundation stone of the Dhubri-Phulbari bridge estimated to be over Rs 4000 cr over the Brahmaputra, which will be India’s longest road bridge, through video conference on February 18. The length of the river bridge will be about 18 km. The Dhubri-Phulbari bridge will link Dhubri, the district town in Assam located at the north bank of river Brahmaputra, with Phulbari, a small township, partly in Assam and mostly in West Garo Hills district of Meghalaya.