Air pollution is also related to obesity. Although this is controversial, and the research is mainly carried out on animals, it is believed that pollution changes the body's metabolism. This may be caused by inflammation of the respiratory linings caused by pollution particles, which can trigger a stress response. The hormones released in the stress response reduce the effectiveness of insulin and increase blood sugar levels. The purpose of stress response is to prepare energy for us in a state of stress. If air pollution continues to cause slight stress, it will have a long-term impact on how we deal with sugar. This is also the first step towards diabetes.