Evaluating national & urban Indian methane emissions using satellites

India ranks as the third-largest methane emitter globally, with methane emissions increasing by 30% since 1990. According to India’s most recent report to the United Nations Framework Convention on Climate Change (UNFCCC), anthropogenic methane emissions are estimated at 18.7 Tg/year. However, these estimates are based on bottom-up calculations using activity data and laboratory-derived emission factors, and India lacks a dense network of ground-based measurements to validate them.

Recent advances in satellite technology, offering higher spatial and temporal resolution, have enabled the exploration of areas without ground-based measurements. We use a blended product from the TROPOspheric Monitoring Instrument (TROPOMI) and the Greenhouse Gases Observing Satellite (GOSAT) in Bayesian inversions with the Integrated Methane Inversion framework (IMI) to estimate 2021 Indian methane emissions. Prior emissions include fossil fuel exploitationsources from the Global Fuel Exploitation Inventory (GFEI v2) and other anthropogenic sources from the Emissions Database for Global Atmospheric Research (EDGAR v7). Landfill emissions from 19 solid waste disposal sites across 12 cities are assigned prior emissions using estimates based on high-resolution GHGSat observations.

Our inversion improves agreement with the blended TROPOMI data, GOSAT data, and available surface observations. We estimate Indian methane emissions for 2021 at 34 (32–39) Tg/year, 15% higher than prior estimates. The anthropogenic posterior emission is 31 (30 – 37) Tg/year, 67% higher than UNFCCC reported values, consistent with previous studies such as Janardanan et al. (2020), Zhang et al. (2021), and Belikov et al. (2024). Compared to the prior estimate, we find higher emissions from landfills and the oil & gas sector, while coal emissions are found to be lower. An analysis of 12 Indian cities reveals that emissions in 3 cities align with prior estimates, while 8 cities exhibit significantly higher emissions. In these 8 cities, waste management (solid waste and wastewater) contributes most to total emissions. Additionally, GHGSat data indicate that landfill emissions account for 10% to 50% of emissions in these cities, highlighting the critical role of solid waste management in reducing emissions.