After using banana trees to block blackwater pipes connected to lakes and surface drains in Gulshan, Mayor Atiqul Islam expanded the drive to Baridhara.
Dhaka North City Corporation workers blocked such illegal connections of four houses on road No. 11 at Baridhara in the presence of the mayor on Wednesday.
He threatened to permanently block the connections if the landlords in the area do not take measures for proper blackwater management, the city corporation said in a statement.
The mayor lamented illegal blackwater lines connected to lakes and surface drains in the upscale areas, saying he would expand the drive further to Banani and Niketan.
After launching the drive in Gulshan on Jan 4, blackwater from 3,265 of 3,830 houses in the upscale neighbourhoods directly flows into the drains or lakes.
He said blackwater mixing with the lakes was hindering a plan to kill mosquitos by farming fish in the lakes.
The blackwater is supposed to flow to the water treatment plant through designated lines. Septic tanks are also used to store and later remove blackwater.