Sarah Boseley Bill and Melinda Gates announced on Wednesday that they were joining Michael Bloomberg, the mayor of New York, in a $500m campaign against smoking in the developing world. As smoking has become less acceptable and profitable in the rich world, tobacco companies have expanded in countries where there are few restrictions and little in the way of public health warnings. Each year five million people around the world die of smoking; by 2030, more than 80 per cent of them will live in low- and middle-income countries. According to the Gates Foundation, the poorest households in Bangladesh spend almost 10 times as much on tobacco as they do on education. The initiative, which will include campaigns to persuade people of the inadvisability of smoking, and efforts to induce governments to impose bans