The present study reveals the degree of antioxidant response stimulated in Cymbopogon martinii as a result of combined effect of herbicide (2, 4-Dichlorophenoxy acetic acid) and air pollution (auto exhaust). Two indigenously developed varieties of Cymbopogon martinii, namely Trishna and PRC-1, commonly grown in Lucknow were selected as the target plant. Two sites, 1: BBAU campus, as control site (less polluted) and 2: NBRI, Sikanderbagh crossing (one of the highly polluted site of Lucknow city were selected for the transfer experiment study. Results of the study very vividly revealed that the herbicide 2, 4-D enhanced the generation of antioxidant quite significantly in Cymbopogon martinii and works in synergies the effect of auto exhaust pollution.