Freshwater basins are vulnerable to human-induced change for a number of reasons. The change detection study of Ansupa lake, Orissa was carried out by using multi-temporal satellite data clearly indicates the decrease in wetland area. Due to high anthropogenic pressure, the wetland is shrinking day-by-day.

East Calcutta Wetland (ECW) is an example of wise use of cities solid and liquid waste through integrated resource recovery, mainly for pisciculture, vegetable as well as paddy cultivation and manure production. Amaranthus caudatus, Amaranthus blithum and Spinacia oleracea grown at ECW were analyzed for their accumulation of elements using Energy Dispersive X Ray Fluorescence (EDXRF) and compared to those grown in south eastern parts of West Bengal (Midnapur).

Nitrogen is an important nutrient in domestic and industrial wastewater and its elevated concentration in the wetland promotes explosive growth of algae. The decomposition of the algae leads to an excessive growth of bacteria, utilizing and dissolved oxygen from water. This process of rapid algal growth leading to oxygen-starved waters is known as eutrophication.

The treatment and disposal of wastewaters is becoming more and more important as ever increasing population and urbanization threaten existing potable water supplies in many areas of the world. Worldwide natural wetlands are still used for watewater treatment but at present, the use of constructed wetlands is becoming more popular and effective around the world.

World Bank pulled up for aid to flood control programmes in Pakistan