Dhaka, March 13 -- As evening falls in Dhaka, the familiar buzzing begins.

Within minutes, rooms fill with mosquitoes. Nets are drawn, coils are lit, yet relief remains elusive.

Sleep has become a nightly struggle, and in many neighbourhoods, residents say the fogging trucks that once blanketed the streets with insecticide have vanished.

"By evening the house is full of mosquitoes," said Ali Haidar Patwari, a private-sector employee who lives at Mohakhali's Dakshinpara.

"Even with mosquito nets and coils there is no escape. We haven't seen fumigation smoke here for a long time."

His experience is far from unique. Residents across Dhaka describe the same relentless problem.

Conversations with at least 10 people from different parts o...