The ornamental plants such as Bougainvillea spectabilis, Caesalpinia pulcherima, Thevetia peruviana, Nerium oleander, Callendria brevipes and Tecoma gaudichaudi etc. planted along the divider of NH-4 highway are selected in the present work and see the effect of vehicle gases on photosynthetic pigments, this effect has been studied by calculating Chlorophyll-a, Chlorophyll-b and, Total Chlorophyll.
