In India there are many trees and weed plants that keep flowering. It is a tropical country and one can see flowers of many plants throughout the year. Some of the common plants/ trees that produce allergy causing pollens include: Ailanthus excelsa (tree of heaven or Mahanimb), Azadirachta indica (neem), Madhuca indica (mahua), Mimusops elengi (bakula), Morus alba (white mulberry), Eucalyptus spp, Cassia spp. and Murraya paniculata (orange jasmine, kamini).
Parthenium, Amaranthus, Argemone mexicana (prickly poppy), Prosopis julifera (kikar), ragweed, pigweed, cocklebur, sagebrush, marsh elder and tumbleweed.