On Mauritius, and every where else in Africa, there are large supplies of available food and fuel going to waste. Typha of various species clog African waters and cause numerous troubles ranging from flooding to malaria. If grown in clean water and soil, Typha is food. If the water or soil is polluted, Typha will collect and hoard those pollutants like a miser. It will not be fit for human consumptiom. If it is contaminated with something as nasty as arsenic (as is likely in Bangladesh), it is unlikely to be useful for anything. Otherwise, it can then be used as a source of biomass for fuel. It is an excellent feedstock for ethanol production and can also be charred into charcoal for more traditional cooking. The Phragmites reed is also a good source of fuel biomass, but it is harder to process into food. It is, at least, for stone-aged Indians or runaway boys hiding in a swamp. Harvesting these weeds is hard and messy work, but cultivating takes no work whatsoever. You have it! Harvest it! Enjoy the side effects of reduced flooding and reduced malaria.

Interesting comment, but may not be applicable here. For example, malaria was wiped out in Mauritius in the 1950s.