Health department issues instructions on the occasion of National Dengue Day on May 16. District health officials have been urged to conduct source reduction activities to prevent breeding of mosquitoes causing the infection Health department issues instructions on the occasion of National Dengue Day on May 16. District health officials have been urged to conduct source reduction activities to prevent breeding of mosquitoes causing the infection Tamil Nadu Health News, Wellbeing Tips, Diseases, Treatment and Nutrition | The Hindu