If one were wondering what business millions of Burmese had in what was once an uninhabited mangrove swamp typical of the Irrawaddy delta (which cyclone Nargis tore through effortlessly), one again needs to look back to a country's colonialist past.
From the Times:
Before the mid-19th century, the area was a thinly inhabited swamp. But the British colonial rulers saw this as an ideal place to cultivate rice and help feed their empire. They built dikes and drained the land. In the twilight years of British rule, colonial Burma was the world’s largest rice exporter, and millions of Burmese moved here to cultivate the rich alluvial soil. The government says that 6.3 million people lived in the delta before the storm.