I believe they may be Brick Kilns http://www.sos-arsenic.net/english/environment/savar.html
Quote: "Simultaneously, we voice our concern over the lethal air pollution issuing from a few thousand brick kilns in the suburbs of Dhaka. The raising of their chimneys has hardly helped matters"
Towers - Misc, Info Requested 
http://www.sos-arsenic.net/english/environment/savar.html
Quote: "Simultaneously, we voice our concern over the lethal air pollution issuing from a few thousand brick kilns in the suburbs of Dhaka. The raising of their chimneys has hardly helped matters"
There's a good picture of one of these kilns here: http://www.cleanairnet.org/caiasia/1412/articles-58218_resource_3.jpeg, including the chimneys and the outdoor drying and storage areas.