A person was killed after the bailey bridge over river Tlawng, linking Aizawl to the lone Lengpui airport, collapsed.
A police officer said that 24-year-old Lalremsanga, a helper of a heavy dumper truck which fell into the river after the incident on Wednesday, died on the spot while the driver Lalrammawia (20) was taken out with broken bones, but remained out of danger.
The bailey bridge over Tlawng had first collapsed on October 31 last year and again on December 8.
The opposition Mizo National Front (MNF) on Thursday demanded the resignation of Chief Minister Lal Thanhawla, who holds the public works portfolio, by owning moral responsibility.
The party also demanded a judicial inquiry into incidents of repeated collapse of several bridges in the state during the past two years.