Comparing Environmental and Energy Policy Options in India: Sectoral Impacts and Interactions

India is a rapidly developing economy and aims to achieve several interrelated UN Sustainable Development Goals (SDGs), including reducing air pollution (SDG 3.9), achieving universal access to modern energy (SDG 7.1), promoting sustainable industrialization (SDG 9.2) and combating climate change (SDG 13). Achieving each of these goals has unique challenges, including potential tradeoffs with other dimensions. This study examines the implications of energy infrastructure, climate change, and air quality policies and measures in India through 2050, including the extent to which any one policy would support or impede the attainment of other policy objectives. We analyze Indian policies and trends to define reference and ambitious pathways over four dimensions: air pollution control (AP), greenhouse gas pricing (GHG), natural gas infrastructure expansion (NG), and light-duty vehicle electrification (EV). We use GCAM, a global energy-climate-land model, to project energy system changes as well as GHG and air pollutant emissions for each of the scenarios. These emissions pathways are used as inputs to Hector, a reduced-form climate model, to determine changes in radiative forcing relative to the reference scenario and to TM5-FASST, an air quality source-receptor model, to produce estimates of population-weighted changes in PM2.5 and O₃ levels across India. All policies and measures lead to energy system changes in at least one sector, with the GHG and NG cases having the largest effects on fuel and technology deployment across sectors. The AP and GHG cases lead to the largest reductions in air pollution emissions and radiative forcing, respectively, although the AP policy in isolation increases radiative forcing due to a reduction in SO₂ emissions. This tradeoff can be mitigated by combining GHG and AP policies, which leads to lower radiative forcing and improved air quality simultaneously.