It's not happening with Dhaka dear in my observation all underdevelop countries doing such bad behavior with his cities. I am in Lahore Pakistan and find the same thing which you are explaining. Governments cutting all the trees which help to reduce pollution and building new plazas shopping mall and other unnatural things which badly affect the fresh breath. Pollution is too much that since 2 months we are victim of smog and due to the smog everyone facing flu, soar throat, fever etc problems. The only solution is all of this pollution is we install new plants in large numbers in hurry and stop to cutdown the trees. Then Dhaka and other cities will find some relief in sense or pollution and soon we can find blue sky, stars in night to see.