Biomass utilization for food, fuels and chemicals. Biomass : Biomass refers to all the matter that can be obtained from photosynthesis. Most vegetable species use solar energy to create sugars from carbon dioxide and water.They store this energy in the form of glucose or starch molecules, oleaginous, cellulose, and lignocellulose. Biomass appears to be an attractive feedstock for three main reasons. First, it is a renewable resource that could be sustainably developed in the future. Second, it appears to have formidably positive environmental properties, notably the recycling of carbon in the biological processes, resulting in no net releases of carbon dioxide and a very low sulphur content. Third, it appears to have significant economic potential provided that fossil fuel prices increase, quite substantially, in the future.The great versatility of biomass as a feedstock is evident from the range of materials that can be converted into various solid, liquid, and gaseous fuels using biological and thermochemical conversion processes. Four broad categories of potential biomass feedstocks can be identified: (1) organic urban or industrial wastes; (2) agricultural crop residues and wastes including manure, straw, bagasse, and forestry waste; (3) existing uncultivated vegetation including stands of trees, shrubs, bracken, heather, and the like; and (4) energy plantations, which involve planted energy crops either on land brought into production for that purpose, land diverted from other agricultural production, or as catch crops planted on productive land. Biomass fuels, including wood, crop waste and dungcake account for 47% of the total energy consumption in India (TEDDY, 1997; Ravindranath and Hall, 1995) and are the major source (85–90%) of cooking-energy in rural India (TEDDY, 1997). The 1990 national consumption of biofuels was estimated at about 450MTyr_1 with a 59 : 18 :23% division among fuelwood, dung-cake and crop waste, respectively. Biomass burning also results from controlled and accidental forest fires (Prasad et al., 2000; Joshi, 1991). In addition, forest biomass is burnt for agricultural land clearing and a fraction of crop waste is fired in fields following harvest. Recent estimates of national level SO2 and aerosol emissions, for India, indicate the importance of biomass combustion contribution to SO2, particulate matter (PM2.5) o2.5 mm diameter, BC and OM (Venkataraman et al., 1999; Reddy and Venkataraman, 1999, 2000). from biomass combustion (M. uller et al., 2001a, b). A comprehensive inventory for SO2 and aerosols from the biomass combustion for India for a recent base year is needed as input to the regional scale climate-modelling studies over India and Indian Ocean during INDOEX period. The objectives of the paper are (i) construction of a spatially resolved biofuel and biomass combustion data set for India for 1996–1997, (ii) development of realistic emission factors of SO2 and aerosols to represent biomass burning in domestic cooking stoves and forests, (iii) construction of a spatially resolved (0.251_0.251) emission inventory for SO2 and aerosol chemical constituents from biomass combustion in India and projection of the emissions to the INDOEX period (1998–1999). Biofuels: The use of bioenergy is a strategic resource used in the work to fulfill the Kyoto Protocol to replace fossil fuels on a large scale. Bioenergy and biomass generally could be used to mitigate greenhouse gas emissions and the global climate change. In some countries, the use of biofuels already holds a significant share of the energy supply to industrial processes, heat production, and (in some cases) electricity production. The Nordic countries are examples of this. Large-scale production and use of biofuels has to be done in an environmentally sound way. New technology and system solutions give biofuels possibilities to compete in new markets. Traditionally, biofuels have been used in the same geographical regions in which they were produced. However in Northern Europe Biomass is recently being used for industrial and large scale heating operations due to supply of recycled wood and forest residues. The trade situation has come about as a result of means of control on waste and energy. Climate change due to anthropogenic emissions of greenhouse gases is one of the greatest environmental challenges today, and greenhouse gas concentrations in the atmosphere will continue to rise unless there are major reductions in greenhouse gas emissions. Carbon dioxide (CO2) is the most important greenhouse gas, and increasing the use of biomass for energy is an important option for reducing CO2 emissions. The European Union (EU) has no common energy policy, but there are different common goals mainly given in the European Commission’s (EC) ‘‘White Paper for a Community Strategy,’’ which sets out a strategy to double the share of renewable energy in gross domestic energy use in the EU by 2010 (from the recent 6–12%, with some 85% of the renewables being bioenergy). The strategy includes a timetable of actions to achieve this objective in the form of double the share of renewable energy in gross domestic energy use in the EU by 2010, including a timetable of actions to achieve this objective in the form of an action plan. The EC’s green paper in November 2000, ‘‘Towards a European Strategy for the Security of Energy Supply,’’ introduced the objective of substituting 20% of traditional fuels by alternative fuels in the road transport sector by 2020. A proposal for a directive ‘‘on the promotion of the use of biofuels for transport,’’ adopted by the EC in November 2001, requires that an increasing proportion of all diesel and gasoline sold in the member states be biofuels, starting with 2% in 2005 and increasing progressively so as to reach a minimum of 5.75% of fuels sold in 2010. The EU member countries are jointly decreasing the emissions of six different greenhouse gases with by 8% on average during the period starting in 1990 and ending in 2008–2012 (depending on type of action and type of gas). An example of this policy is the EU-funded research programs, where the focus is on nonfossil fuels and nonfossil techniques to target the goal of reducing emissions of greenhouse gases. The Scandinavian countries and Austria have been the pioneering countries in the modern use of bioenergy. Other countries, such as Germany, the United Kingdom, The Netherlands, and Spain, are expected to increase their use of biofuels significantly. There are variable forest resources and variable uses of biofuels in Europe, and these are the key factors behind the trade that has grown rather quickly during the past years. Because of the incentives to increase the use of biofuels, so the prediction for the short and medium term is an Encyclopedia of Energy, Volume 3. ( 2004 ) Biofuels used in rural India include wood, crop waste and dung-cake (Fig. 1). The per capita consumption of different biofuels at district level was derived from the rural energy database (REDB), developed by Tata Energy Research Institute (Joshi et al., 1992; Sinha et al., 1998). The biofuel consumption in each district was estimated by multiplying the per capita consumption with the district rural population for 1996–1997 from census data. The base year 1996– 1997 was chosen to estimate the emissions for the same year as emissions from fossil fuel combustion (see companion paper). Wood is the only reported biofuel used in urban areas. 1991).