Air pollution in Dhaka City

Fan at my room, Shafeen (my 2 and a half year old son) took this picture through my cell phone

I must inform this at the beginning that I didn't do any scientific testing for my thoughts. Its just an assumption. In Bangladesh we have sea (Bay of Bengal) at the south of the country. That's why we always got cool and fresh air from the south. Most of our houses has windows at the south to get fresh air. Now a day I am not getting fresh air from south. Most of the time its getting bad smell (like dumped dustbin), and in this summer didn't getting any cool air from south but from East. More over If I keep open door at the south cool air comes but it makes warm the room. Don't know what kind of hot air (could be from cars/buses burned air) it brings and couldn't take away.