The Malagasy people use charcoal to cook their food. Pollution from burning all fossil fuels is harmful to the atmosphere, but burning coal has a larger impact on air pollution than burning oil or gas because it releases more carbon dioxide, sulfur dioxide, and heavy metal pollutants per unit of energy. In fact, the city is one of the most polluted in the world. Some countries, such as Japan, are increasing their use of nuclear power, and there is a global increase in electricity supplied by renewable sources such as wind, solar and water.