The dead are Sohrab Hossain, 35, a Dhaka Wasa sweeper and Dulal Gazi, 22, who were working under one of the eight contractors appointed by Wasa to clean sewerage lines in the old part of the city.

Dulal Gazi got into about 12-foot deep sewerage drain in Haranath Ghosh Road around 1:00pm to clean the drain, witnesses said.

"I heard Dulal cry 'Save me, save me, I can not breathe' moments after he stepped into the drain," said Sayeed Hasan Shaheed, who was sitting in a nearby tea stall.

Soon Sohrab got into the drain to save his fellow cleaner but he also met the same fate, Sayeed said.

Peeping into the drain, locals found the bodies floating in the knee-deep water in the drain and informed firefighters.

The firefighters later recovered the bodies. They were sent to Dhaka Medical College Hospital for autopsy.

Work is going on under a project to clean up all sewerage lines in old part of the city, Dhaka Wasa Executive Engineer AKMA Hamid said.

Earlier on February 7, three locals of Hazaribagh in old Dhaka died from inhaling toxic gas as they got into a clogged sewerage line to clean it.