doctors treating asthma and allergies in Chennai now have a new tool to help them treat their patients. The city is the latest to have a pollen calendar. Researchers from Chennai-based Asthma & Allergy Research Centre, Raju Hospitals Private Limited and the University of Madras, recently carried out a survey of commonly present pollen grains in the air to prepare the map. "The map will help determine the type of pollen grains that are likely to have caused asthma,' says V Raju, director of Raju Hospitals.

The air quality was monitored over a 12-month period (January-December, 2001). The group installed traps at five different locations