World Asthma Day 2021: Theme, history and all you need to know World Asthma Day 2021: Theme, history and all you need to know World Asthma Day is observed every year on the first Tuesday of May. Check here all you need to know about the day. advertisement Representational Image World Asthma Day is observed every year on the first Tuesday of May. This year it falls on May 4. It is an annual event organized by the Global Initiative for Asthma (GINA) in collaboration with health care groups and asthma educators, to spread awareness and care around the world. WAD is held each May to raise awareness of Asthma worldwide. It aims to educate people on how best to get control over this respiratory problem and other allergic diseases.