Tobacco is grown in many countries including Australia, however it is most often grown in poorer countries. Growing tobacco affects the soil, as it uses soil nutrients faster than many other crops. In order to maintain soil fertility these nutrients need to be replaced with fertilisers. Many farmers in poorer countries can not afford to buy fertilisers so often tobacco is grown until the soil is no longer fertile. Then new areas have to be found to grow these crops (often through deforestation).
Tobacco crops need to be regularly and heavily sprayed for pests and disease. The misuse of pesticides can affect the health of the farmers and there is the risk that chemicals can leak into community water supplies.
Tobacco crops are often grown instead of food crops especially in poorer countries. In some of these countries food is already in short supply.