The World Health Organization has warned that tobacco is making poor countries poorer, and the organization is urging the developing world to take a harder line against smoking. The warning was contained in a WHO study on tobacco use, issued in advance of World No Tobacco Day.

The WHO says the vast bulk of the world's estimated 1.3 billion smokers live in developing countries, where a significant amount of people's meager incomes go to feed the habit. It estimated, for example, that the poorest households in Bangladesh spend almost 10 times as much on tobacco as they do on education while in Indonesia tobacco accounts for about 15 percent of total expenses for the lowest income group.

The poverty-inducing impact of smoking on poor countries is the theme of this year's World No Tobacco Day, scheduled for May 31. It is an annual event championed by the WHO to highlight the dangers of tobacco and to encourage greater efforts to curb smoking.

The tobacco industry provides significant employment and revenue in many developing countries, and there are fears that tougher controls or higher prices might hurt their economies.

But Burke Fishburn, a WHO scientist and anti-tobacco campaigner who is based in Manila, says the massive health costs and productivity losses from smoking far outweigh any income that developing countries get from the business. "The most recent estimate in China, which was from the mid-1990s, estimated that direct and indirect health care costs due to tobacco use cost the country about $6.5 billion each year," he says.

Mr. Fishburn says some developing Asian countries, such as Malaysia and the Philippines, have taken tentative steps to try to reduce smoking through public education campaigns and anti-smoking laws.

But others like China, which has a huge state-controlled tobacco industry and the largest number of smokers in the world, have made little headway. The WHO quoted a projection from a previous study, predicting that smoking will kill as many as three million Chinese a year by the middle of this century.