Effect of air pollution on peri-urban agriculture: a case study M. Agrawal a, *, B. Singh a , M. Rajput a , F. Marshall b , J.N.B. Bell b a Department of Botany, Banaras Hindu University, Varanasi- 221 005, India b Department of Environment Science and Technology, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK Received 17 January 2003; accepted 15 May 2003 ‘‘Capsule’’: Urban air pollution has a negative impact on peri-urban agriculture. Abstract Peri-urban agriculture is vital for the urban populations of many developing countries. Increases in both industrialization and urbanization, and associated air pollution threaten urban food production and its quality. Six hour mean concentrations were monitored for SO 2 , NO 2 and O 3 and plant responses were measured in terms of physiological characteristics, pigment, biomass and yield. Parameter reductions in mung bean (Vigna radiata), palak (Beta vulgaris), wheat (Triticum aestivum) and mustard (Brassica compestris) grown within the urban fringes of Varanasi, India correlated directly with the gaseous pollutants levels. The magni- tude of response involved all three gaseous pollutants at peri-urban sites; O 3 had more influence at a rural site. The study con- cluded that air pollution in Varanasi could negatively influence crop yield. # 2003 Elsevier Ltd. All rights reserved. Keywords: Air pollution; Biomass; Crop plants; Impact; India; Peri-urban agriculture; Yield 1. Introduction Many developing countries, including India, have experienced a progressive degradation in air quality as a consequence of rapid development over the last two decades. In particular, the levels of air pollutants are increasing rapidly in urban and peri-urban areas in many mega cities of the developing world (UNEP, 1999). In India, urban air pollution has increased rapidly with urban populations, numbers of motor vehicles, use of fuels with poor environmental perfor- mance, badly maintained roads and ineffective environ- mental regulations. As a result, agricultural land adjacent to urban areas is exposed increasingly to air pollutants of urban origin. A major threat to crop pro- duction is gaseous air pollutants, particularly sulphur dioxide, nitrogen dioxide and the secondary photo- chemical oxidant, ozone. These phytotoxic gases could have important and increasing adverse impacts on the livelihoods and well being of producers and consumers through effects on urban and periurban crop production (Marshall et al., 2001; Te Lintelo et al., 2002). In Indian cities’ concentrations of phytotoxic air pollutants often exceed the thresholds of toxicity to vegetation (Pandey et al., 1992; Stone, 1992). Air pollution has the potential to reduce both yield and the nutritional quality of crop plants (Ja¨ger et al., 1993; Ashmore and Marshall, 1999). Extensive studies conducted in North America have clearly shown significant yield losses in a range of major crops due to ambient air pollution (Heck et al., 1988), whilst more recent stud- ies from the south Asia have shown large yield reductions in two cultivars of wheat in Lahore, Paki- stan using open-top chambers ventilated with ambient or charcoal-filtered air (Wahid et al., 1995). Consider- able knowledge about the rapidly increasing levels of air pollutants in urban and industrial areas of devel- oping countries has been generated, but their possible consequences for agricultural production have scarcely been explored. The present study was therefore con- ducted in peri-urban and rural locations of Varanasi city, India to evaluate the impact of urban air pollu- tants on selected crop plants grown under standar- dized conditions, utilizing a transect along a gradient of pollution. 0269-7491/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0269-7491(03)00245-8 Environmental Pollution 126 (2003) 323–329 www.elsevier.com/locate/envpol * Corresponding author. Tel.: +91-542-318056; fax: +91-542- 317074. E-mail address: madhoo@bhu.ac.in (M. Agrawal).