Higher levels of air pollution in urban India poses a threat to a large population of adults and children, exposing them to pulmonary diseases, like asthma, medical experts have warned ahead of World Asthma Day, which is observed on May 5. "Asthma is not curable, but with advances in therapy, it can be effectively treated in a majority of cases with minimal side effects," said Dr. Arun Nair, Chief of Interventional Pulmonary Medicine at Amrita Institute of Medical Sciences and Research Center (AIMS) at Kochi.