exceed . Economy Approximately two-thirds of the Bangladesh people work in agriculture and grow crops on the fertile floodplains of the delta. The major crops that are grown in the Ganges Delta are jute, tea, and rice. Fishing is also an important activity in the delta region, with fish being a major source of food for many of the people in the area. In the last decades of the 20th century, scientists helped the poor people of the delta to improve fish farming methods. By turning unused ponds into viable fish farms and improving methods of raising fish in existing ponds, many people can now earn a living raising and selling fish. Using new systems, fish production in existing ponds has increased 800%. Shrimp are farmed in containers or cages that are submerged in open water. Most are exported. As there is a maze of many river branches, the area is difficult to pass. Most islands are only connected with the mainland by simple wooden ferryboats. Bridges are rare. Some islands are not yet connected to the electric grid, so island residents tend to use solar cells for a bit of electric supply. Arsenic pollution Arsenic is a naturally occurring substance in the Ganga Delta that has detrimental effects on health and may enter the food chain, especially in key crops such as rice. Climate The Ganges Delta lies mostly in the tropical wet climate zone, and receives between of rainfall each year in the western part, and in the eastern part.. Hot, dry summers and cool, dry winters make the climate suitable for agriculture. Cyclones and flooding In November 1970, the deadliest tropical cyclone of the twentieth century hit the Ganges Delta region. The 1970 Bhola cyclone killed 500,000 people (official death toll), with another 100,000 missing. The Guinness Book of World Records estimated the total loss of human life from the Bhola cyclone at 1,000,000. Another cyclone hit the delta in 1991, killing about 139,000 people. It also left many people homeless. People have to be careful on the river delta as severe flooding also occurs. In 1998, the Ganges flooded the delta, killing about 1,000 people and leaving more than 30 million people homeless. The Bangladesh government asked for $900 million to help feed the people of the region, as the entire rice crop was lost. History of the Bengal Delta The history of the Bengal delta