(EBAY - This is an original 1928 photogravure of the unusual windscreens or wind catchers on the flat roofs of the houses in Hyderabad. Photograph by Martin Hürlimann.)

From The Vanishing Glory of Hyderabad (Sindh, Pakistan) by Mir Atta Muhammad Talpur*
“Once the most striking feature of Hyderabad was its peculiar skyline dominated by wind-catchers. These wind catchers or Manghu, as they are called in the local Sindhi language, were fixed on housetops, to catch the southwesterly breeze in the hot summer days and evenings. The breeze entering the wind-catchers would penetrate into the room and keep it cool. Due to the numerous wind catchers, Hyderabad be-came famous as manghan jo shaharu or the city of wind catchers.

http://iaakuza.blogspot.com/2008/11/ik-retro-wind-catcher-of-hyderabad.html